Merge branch 'master' into decimal

CHANGELOG.md

@@ -128,6 +128,8 @@ Yu](https://github.com/yuzhichang))
 * Introduce CustomSeparated data format that supports custom escaping and
   delimiter rules.  [#7118](https://github.com/ClickHouse/ClickHouse/pull/7118)
 ([tavplubix](https://github.com/tavplubix))
+* Support Redis as source of external dictionary. [#4361](https://github.com/ClickHouse/ClickHouse/pull/4361) [#6962](https://github.com/ClickHouse/ClickHouse/pull/6962) ([comunodi](https://github.com/comunodi), [Anton
+Popov](https://github.com/CurtizJ))
 
 ### Bug Fix
 * Fix wrong query result if it has `WHERE IN (SELECT ...)` section and `optimize_read_in_order` is

README.md

@@ -11,7 +11,3 @@ ClickHouse is an open-source column-oriented database management system that all
 * [Blog](https://clickhouse.yandex/blog/en/) contains various ClickHouse-related articles, as well as announces and reports about events.
 * [Contacts](https://clickhouse.yandex/#contacts) can help to get your questions answered if there are any.
 * You can also [fill this form](https://forms.yandex.com/surveys/meet-yandex-clickhouse-team/) to meet Yandex ClickHouse team in person.
-
-## Upcoming Events
-
-* [ClickHouse Meetup in Moscow](https://yandex.ru/promo/clickhouse/moscow-december-2019) on December 11.

dbms/src/Columns/ColumnDecimal.h

@@ -66,6 +66,7 @@ private:
     friend class COWHelper<ColumnVectorHelper, Self>;
 
 public:
+    using ValueType = T;
     using Container = DecimalPaddedPODArray<T>;
 
 private:

dbms/src/Columns/ColumnVector.cpp

@@ -204,7 +204,7 @@ MutableColumnPtr ColumnVector<T>::cloneResized(size_t size) const
         memcpy(new_col.data.data(), data.data(), count * sizeof(data[0]));
 
         if (size > count)
-            memset(static_cast<void *>(&new_col.data[count]), static_cast<int>(value_type()), (size - count) * sizeof(value_type));
+            memset(static_cast<void *>(&new_col.data[count]), static_cast<int>(ValueType()), (size - count) * sizeof(ValueType));
     }
 
     return res;

dbms/src/Columns/ColumnVector.h

@@ -104,13 +104,13 @@ private:
     struct greater;
 
 public:
-    using value_type = T;
-    using Container = PaddedPODArray<value_type>;
+    using ValueType = T;
+    using Container = PaddedPODArray<ValueType>;
 
 private:
     ColumnVector() {}
     ColumnVector(const size_t n) : data(n) {}
-    ColumnVector(const size_t n, const value_type x) : data(n, x) {}
+    ColumnVector(const size_t n, const ValueType x) : data(n, x) {}
     ColumnVector(const ColumnVector & src) : data(src.data.begin(), src.data.end()) {}
 
     /// Sugar constructor.

dbms/src/Columns/ReverseIndex.h

@@ -116,7 +116,7 @@ namespace
                 return (*state.saved_hash_column)[index];
             else
             {
-                using ValueType = typename ColumnType::value_type;
+                using ValueType = typename ColumnType::ValueType;
                 ValueType value = unalignedLoad<ValueType>(state.index_column->getDataAt(index).data);
                 return DefaultHash<ValueType>()(value);
             }
@@ -367,7 +367,7 @@ private:
     {
         if constexpr (is_numeric_column)
         {
-            using ValueType = typename ColumnType::value_type;
+            using ValueType = typename ColumnType::ValueType;
             ValueType value = unalignedLoad<ValueType>(ref.data);
             return DefaultHash<ValueType>()(value);
         }

dbms/src/Common/quoteString.cpp

@@ -14,6 +14,15 @@ String quoteString(const StringRef & x)
 }
 
 
+String doubleQuoteString(const StringRef & x)
+{
+    String res(x.size, '\0');
+    WriteBufferFromString wb(res);
+    writeDoubleQuotedString(x, wb);
+    return res;
+}
+
+
 String backQuote(const StringRef & x)
 {
     String res(x.size, '\0');

dbms/src/Common/quoteString.h

@@ -9,6 +9,9 @@ namespace DB
 /// Quote the string.
 String quoteString(const StringRef & x);
 
+/// Double quote the string.
+String doubleQuoteString(const StringRef & x);
+
 /// Quote the identifier with backquotes.
 String backQuote(const StringRef & x);
 

dbms/src/Core/DecimalComparison.h

@@ -4,6 +4,7 @@
 #include <Core/Block.h>
 #include <Core/AccurateComparison.h>
 #include <Core/callOnTypeIndex.h>
+#include <DataTypes/DataTypesNumber.h>
 #include <DataTypes/DataTypesDecimal.h>
 #include <Columns/ColumnVector.h>
 #include <Columns/ColumnsNumber.h>
@@ -22,12 +23,12 @@ namespace ErrorCodes
 ///
 inline bool allowDecimalComparison(const DataTypePtr & left_type, const DataTypePtr & right_type)
 {
-    if (isDecimal(left_type))
+    if (isColumnedAsDecimal(left_type))
     {
-        if (isDecimal(right_type) || isNotDecimalButComparableToDecimal(right_type))
+        if (isColumnedAsDecimal(right_type) || isNotDecimalButComparableToDecimal(right_type))
             return true;
     }
-    else if (isNotDecimalButComparableToDecimal(left_type) && isDecimal(right_type))
+    else if (isNotDecimalButComparableToDecimal(left_type) && isColumnedAsDecimal(right_type))
         return true;
     return false;
 }
@@ -82,7 +83,7 @@ public:
 
     static bool compare(A a, B b, UInt32 scale_a, UInt32 scale_b)
     {
-        static const UInt32 max_scale = maxDecimalPrecision<Decimal128>();
+        static const UInt32 max_scale = DecimalUtils::maxPrecision<Decimal128>();
         if (scale_a > max_scale || scale_b > max_scale)
             throw Exception("Bad scale of decimal field", ErrorCodes::DECIMAL_OVERFLOW);
 

dbms/src/Core/DecimalFunctions.h

@@ -0,0 +1,142 @@
+#pragma once
+// Moved Decimal-related functions out from Core/Types.h to reduce compilation time.
+
+#include <Core/Types.h>
+#include <Common/intExp.h>
+
+#include <limits>
+
+class DateLUTImpl;
+
+namespace DB
+{
+
+namespace DecimalUtils
+{
+
+static constexpr size_t minPrecision() { return 1; }
+template <typename T> static constexpr size_t maxPrecision() { return 0; }
+template <> constexpr size_t maxPrecision<Decimal32>() { return 9; }
+template <> constexpr size_t maxPrecision<Decimal64>() { return 18; }
+template <> constexpr size_t maxPrecision<Decimal128>() { return 38; }
+
+template <typename T> T scaleMultiplier(UInt32 scale);
+template <> inline Int32 scaleMultiplier<Int32>(UInt32 scale) { return common::exp10_i32(scale); }
+template <> inline Int64 scaleMultiplier<Int64>(UInt32 scale) { return common::exp10_i64(scale); }
+template <> inline Int128 scaleMultiplier<Int128>(UInt32 scale) { return common::exp10_i128(scale); }
+
+/** Components of DecimalX value:
+ * whole - represents whole part of decimal, can be negatve or positive.
+ * fractional - for fractional part of decimal, always positive.
+ */
+template <typename T>
+struct DecimalComponents
+{
+    T whole;
+    T fractional;
+};
+
+/** Make a decimal value from whole and fractional components with given scale multiplier.
+ * where scale_multiplier = scaleMultiplier<T>(scale)
+ * this is to reduce number of calls to scaleMultiplier when scale is known.
+ *
+ * Sign of `whole` controls sign of result: negative whole => negative result, positive whole => positive result.
+ * Sign of `fractional` is expected to be positive, otherwise result is undefined.
+ * If `scale` is to big (scale > maxPrecision<DecimalType::NativeType>), result is undefined.
+ */
+template <typename DecimalType>
+DecimalType decimalFromComponentsWithMultiplier(const typename DecimalType::NativeType & whole,
+                                                 const typename DecimalType::NativeType & fractional,
+                                                 typename DecimalType::NativeType scale_multiplier)
+{
+    using T = typename DecimalType::NativeType;
+    const auto fractional_sign = whole < 0 ? -1 : 1;
+
+    const T value = whole * scale_multiplier + fractional_sign * (fractional % scale_multiplier);
+    return DecimalType(value);
+}
+
+/** Make a decimal value from whole and fractional components with given scale.
+ *
+ * @see `decimalFromComponentsWithMultiplier` for details.
+ */
+template <typename DecimalType>
+DecimalType decimalFromComponents(const typename DecimalType::NativeType & whole, const typename DecimalType::NativeType & fractional, UInt32 scale)
+{
+    using T = typename DecimalType::NativeType;
+
+    return decimalFromComponentsWithMultiplier<DecimalType>(whole, fractional, scaleMultiplier<T>(scale));
+}
+
+/** Make a decimal value from whole and fractional components with given scale.
+ * @see `decimalFromComponentsWithMultiplier` for details.
+ */
+template <typename DecimalType>
+DecimalType decimalFromComponents(const DecimalComponents<typename DecimalType::NativeType> & components, UInt32 scale)
+{
+    return decimalFromComponents<DecimalType>(components.whole, components.fractional, scale);
+}
+
+/** Split decimal into whole and fractional parts with given scale_multiplier.
+ * This is an optimization to reduce number of calls to scaleMultiplier on known scale.
+ */
+template <typename DecimalType>
+DecimalComponents<typename DecimalType::NativeType> splitWithScaleMultiplier(const DecimalType & decimal, typename DecimalType::NativeType scale_multiplier)
+{
+    using T = typename DecimalType::NativeType;
+    const auto whole = decimal.value / scale_multiplier;
+    auto fractional = decimal.value % scale_multiplier;
+    if (fractional < T(0))
+        fractional *= T(-1);
+
+    return {whole, fractional};
+}
+
+/// Split decimal into components: whole and fractional part, @see `DecimalComponents` for details.
+template <typename DecimalType>
+DecimalComponents<typename DecimalType::NativeType> split(const DecimalType & decimal, UInt32 scale)
+{
+    if (scale == 0)
+    {
+        return {decimal.value, 0};
+    }
+    return splitWithScaleMultiplier(decimal, scaleMultiplier<typename DecimalType::NativeType>(scale));
+}
+
+/** Get whole part from decimal.
+ *
+ * Sign of result follows sign of `decimal` value.
+ * If scale is to big, result is undefined.
+ */
+template <typename DecimalType>
+typename DecimalType::NativeType getWholePart(const DecimalType & decimal, size_t scale)
+{
+    if (scale == 0)
+        return decimal.value;
+
+    return decimal.value / scaleMultiplier<typename DecimalType::NativeType>(scale);
+}
+
+/** Get fractional part from decimal
+ *
+ * Result is always positive.
+ * If scale is to big, result is undefined.
+ */
+template <typename DecimalType>
+typename DecimalType::NativeType getFractionalPart(const DecimalType & decimal, size_t scale)
+{
+    using T = typename DecimalType::NativeType;
+
+    if (scale == 0)
+        return 0;
+
+    T result = decimal.value;
+    if (result < T(0))
+        result *= T(-1);
+
+    return result % scaleMultiplier<T>(scale);
+}
+
+}
+
+}

dbms/src/Core/Types.h

@@ -31,6 +31,8 @@ enum class TypeIndex
     Float64,
     Date,
     DateTime,
+    DateTime32 = DateTime,
+    DateTime64,
     String,
     FixedString,
     Enum8,
@@ -151,10 +153,15 @@ struct Decimal
     T value;
 };
 
+
 using Decimal32 = Decimal<Int32>;
 using Decimal64 = Decimal<Int64>;
 using Decimal128 = Decimal<Int128>;
 
+// TODO (nemkov): consider making a strong typedef
+//using DateTime32 = time_t;
+using DateTime64 = Decimal64;
+
 template <> struct TypeName<Decimal32>   { static const char * get() { return "Decimal32";   } };
 template <> struct TypeName<Decimal64>   { static const char * get() { return "Decimal64";   } };
 template <> struct TypeName<Decimal128>  { static const char * get() { return "Decimal128";  } };
@@ -196,6 +203,7 @@ inline const char * getTypeName(TypeIndex idx)
         case TypeIndex::Float64:    return TypeName<Float64>::get();
         case TypeIndex::Date:       return "Date";
         case TypeIndex::DateTime:   return "DateTime";
+        case TypeIndex::DateTime64: return "DateTime64";
         case TypeIndex::String:     return TypeName<String>::get();
         case TypeIndex::FixedString: return "FixedString";
         case TypeIndex::Enum8:      return "Enum8";

dbms/src/Core/callOnTypeIndex.h

@@ -71,6 +71,7 @@ bool callOnBasicType(TypeIndex number, F && f)
         {
             case TypeIndex::Date:         return f(TypePair<T, UInt16>());
             case TypeIndex::DateTime:     return f(TypePair<T, UInt32>());
+            case TypeIndex::DateTime64:   return f(TypePair<T, DateTime64>());
             default:
                 break;
         }
@@ -135,6 +136,7 @@ inline bool callOnBasicTypes(TypeIndex type_num1, TypeIndex type_num2, F && f)
         {
             case TypeIndex::Date: return callOnBasicType<UInt16, _int, _float, _decimal, _datetime>(type_num2, std::forward<F>(f));
             case TypeIndex::DateTime: return callOnBasicType<UInt32, _int, _float, _decimal, _datetime>(type_num2, std::forward<F>(f));
+            case TypeIndex::DateTime64: return callOnBasicType<Decimal64, _int, _float, _decimal, _datetime>(type_num2, std::forward<F>(f));
             default:
                 break;
         }
@@ -145,10 +147,11 @@ inline bool callOnBasicTypes(TypeIndex type_num1, TypeIndex type_num2, F && f)
 
 
 class DataTypeDate;
-class DataTypeDateTime;
 class DataTypeString;
 class DataTypeFixedString;
 class DataTypeUUID;
+class DataTypeDateTime;
+class DataTypeDateTime64;
 template <typename T> class DataTypeEnum;
 template <typename T> class DataTypeNumber;
 template <typename T> class DataTypeDecimal;
@@ -178,6 +181,7 @@ bool callOnIndexAndDataType(TypeIndex number, F && f)
 
         case TypeIndex::Date:           return f(TypePair<DataTypeDate, T>());
         case TypeIndex::DateTime:       return f(TypePair<DataTypeDateTime, T>());
+        case TypeIndex::DateTime64:     return f(TypePair<DataTypeDateTime64, T>());
 
         case TypeIndex::String:         return f(TypePair<DataTypeString, T>());
         case TypeIndex::FixedString:    return f(TypePair<DataTypeFixedString, T>());

dbms/src/Core/tests/gtest_DecimalFunctions.cpp

@@ -0,0 +1,171 @@
+#include <gtest/gtest.h>
+
+#include <Core/DecimalFunctions.h>
+
+namespace
+{
+using namespace DB;
+
+struct DecimalUtilsSplitAndCombineTestParam
+{
+    const char * description;
+
+    Decimal64 decimal_value;
+    UInt8 scale;
+
+    DecimalUtils::DecimalComponents<typename Decimal64::NativeType> components;
+};
+
+std::ostream & operator << (std::ostream & ostr, const DecimalUtilsSplitAndCombineTestParam & param)
+{
+    return ostr << param.description;
+}
+
+class DecimalUtilsSplitAndCombineTest : public ::testing::TestWithParam<DecimalUtilsSplitAndCombineTestParam>
+{};
+
+template <typename DecimalType>
+void testSplit(const DecimalUtilsSplitAndCombineTestParam & param)
+{
+    const DecimalType decimal_value = param.decimal_value;
+    const auto & actual_components = DecimalUtils::split(decimal_value, param.scale);
+
+    EXPECT_EQ(param.components.whole, actual_components.whole);
+    EXPECT_EQ(param.components.fractional, actual_components.fractional);
+}
+
+template <typename DecimalType>
+void testDecimalFromComponents(const DecimalUtilsSplitAndCombineTestParam & param)
+{
+    EXPECT_EQ(param.decimal_value,
+              DecimalUtils::decimalFromComponents<DecimalType>(param.components.whole, param.components.fractional, param.scale));
+}
+
+template <typename DecimalType>
+void testGetWhole(const DecimalUtilsSplitAndCombineTestParam & param)
+{
+    EXPECT_EQ(param.components.whole,
+              DecimalUtils::getWholePart(DecimalType{param.decimal_value}, param.scale));
+}
+
+template <typename DecimalType>
+void testGetFractional(const DecimalUtilsSplitAndCombineTestParam & param)
+{
+    EXPECT_EQ(param.components.fractional,
+              DecimalUtils::getFractionalPart(DecimalType{param.decimal_value}, param.scale));
+}
+
+// unfortunatelly typed parametrized tests () are not supported in this version of gtest, so I have to emulate by hand.
+TEST_P(DecimalUtilsSplitAndCombineTest, split_Decimal32)
+{
+    testSplit<Decimal32>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, split_Decimal64)
+{
+    testSplit<Decimal64>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, split_Decimal128)
+{
+    testSplit<Decimal128>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, combine_Decimal32)
+{
+    testDecimalFromComponents<Decimal32>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, combine_Decimal64)
+{
+    testDecimalFromComponents<Decimal64>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, combine_Decimal128)
+{
+    testDecimalFromComponents<Decimal64>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, getWholePart_Decimal32)
+{
+    testGetWhole<Decimal32>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, getWholePart_Decimal64)
+{
+    testGetWhole<Decimal64>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, getWholePart_Decimal128)
+{
+    testGetWhole<Decimal128>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, getFractionalPart_Decimal32)
+{
+    testGetFractional<Decimal32>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, getFractionalPart_Decimal64)
+{
+    testGetFractional<Decimal64>(GetParam());
+}
+
+TEST_P(DecimalUtilsSplitAndCombineTest, getFractionalPart_Decimal128)
+{
+    testGetFractional<Decimal128>(GetParam());
+}
+
+}
+
+// Intentionally small values that fit into 32-bit in order to cover Decimal32, Decimal64 and Decimal128 with single set of data.
+INSTANTIATE_TEST_CASE_P(Basic,
+    DecimalUtilsSplitAndCombineTest,
+    ::testing::ValuesIn(std::initializer_list<DecimalUtilsSplitAndCombineTestParam>{
+        {
+            "Positive value with non-zero scale, whole, and fractional parts.",
+            1234567'89,
+            2,
+            {
+                1234567,
+                89
+            }
+        },
+        {
+            "When scale is 0, fractional part is 0.",
+            1234567'89,
+            0,
+            {
+                123456789,
+                0
+            }
+        },
+        {
+            "When scale is not 0 and fractional part is 0.",
+            1234567'00,
+            2,
+            {
+                1234567,
+                0
+            }
+        },
+        {
+            "When scale is not 0 and whole part is 0.",
+            123,
+            3,
+            {
+                0,
+                123
+            }
+        },
+        {
+            "For negative Decimal value whole part is negative, fractional is non-negative.",
+            -1234567'89,
+            2,
+            {
+                -1234567,
+                89
+            }
+        }
+    }
+),);

dbms/src/DataStreams/AddingDefaultsBlockInputStream.cpp

@@ -14,6 +14,7 @@
 #include <DataTypes/DataTypesDecimal.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypeEnum.h>
 #include <DataTypes/DataTypeUUID.h>
 #include <DataTypes/DataTypeString.h>

dbms/src/DataStreams/TTLBlockInputStream.cpp

@@ -85,6 +85,8 @@ Block TTLBlockInputStream::readImpl()
 
     removeValuesWithExpiredColumnTTL(block);
 
+    updateMovesTTL(block);
+
     return block;
 }
 
@@ -145,7 +147,8 @@ void TTLBlockInputStream::removeValuesWithExpiredColumnTTL(Block & block)
         defaults_expression->execute(block_with_defaults);
     }
 
-    for (const auto & [name, ttl_entry] : storage.ttl_entries_by_name)
+    std::vector<String> columns_to_remove;
+    for (const auto & [name, ttl_entry] : storage.column_ttl_entries_by_name)
     {
         const auto & old_ttl_info = old_ttl_infos.columns_ttl[name];
         auto & new_ttl_info = new_ttl_infos.columns_ttl[name];
@@ -159,7 +162,10 @@ void TTLBlockInputStream::removeValuesWithExpiredColumnTTL(Block & block)
             continue;
 
         if (!block.has(ttl_entry.result_column))
+        {
+            columns_to_remove.push_back(ttl_entry.result_column);
             ttl_entry.expression->execute(block);
+        }
 
         ColumnPtr default_column = nullptr;
         if (block_with_defaults.has(name))
@@ -192,9 +198,34 @@ void TTLBlockInputStream::removeValuesWithExpiredColumnTTL(Block & block)
         column_with_type.column = std::move(result_column);
     }
 
-    for (const auto & elem : storage.ttl_entries_by_name)
-        if (block.has(elem.second.result_column))
-            block.erase(elem.second.result_column);
+    for (const String & column : columns_to_remove)
+        block.erase(column);
+}
+
+void TTLBlockInputStream::updateMovesTTL(Block & block)
+{
+    std::vector<String> columns_to_remove;
+    for (const auto & ttl_entry : storage.move_ttl_entries)
+    {
+        auto & new_ttl_info = new_ttl_infos.moves_ttl[ttl_entry.result_column];
+
+        if (!block.has(ttl_entry.result_column))
+        {
+            columns_to_remove.push_back(ttl_entry.result_column);
+            ttl_entry.expression->execute(block);
+        }
+
+        const IColumn * ttl_column = block.getByName(ttl_entry.result_column).column.get();
+
+        for (size_t i = 0; i < block.rows(); ++i)
+        {
+            UInt32 cur_ttl = getTimestampByIndex(ttl_column, i);
+            new_ttl_info.update(cur_ttl);
+        }
+    }
+
+    for (const String & column : columns_to_remove)
+        block.erase(column);
 }
 
 UInt32 TTLBlockInputStream::getTimestampByIndex(const IColumn * column, size_t ind)

dbms/src/DataStreams/TTLBlockInputStream.h

@@ -58,6 +58,9 @@ private:
     /// Removes rows with expired table ttl and computes new ttl_infos for part
     void removeRowsWithExpiredTableTTL(Block & block);
 
+    /// Updates TTL for moves
+    void updateMovesTTL(Block & block);
+
     UInt32 getTimestampByIndex(const IColumn * column, size_t ind);
     bool isTTLExpired(time_t ttl);
 };

dbms/src/DataTypes/DataTypeDate.h

@@ -9,8 +9,10 @@ namespace DB
 class DataTypeDate final : public DataTypeNumberBase<UInt16>
 {
 public:
+    static constexpr auto family_name = "Date";
+
     TypeIndex getTypeId() const override { return TypeIndex::Date; }
-    const char * getFamilyName() const override { return "Date"; }
+    const char * getFamilyName() const override { return family_name; }
 
     void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override;
     void deserializeWholeText(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override;

dbms/src/DataTypes/DataTypeDateTime.cpp

@@ -1,54 +1,25 @@
-#include <IO/ReadHelpers.h>
-#include <IO/WriteHelpers.h>
-#include <IO/parseDateTimeBestEffort.h>
+#include <DataTypes/DataTypeDateTime.h>
 
-#include <common/DateLUT.h>
-#include <Common/typeid_cast.h>
-#include <Common/assert_cast.h>
+#include <Columns/ColumnDecimal.h>
+#include <Columns/ColumnVector.h>
 #include <Columns/ColumnsNumber.h>
+#include <Common/assert_cast.h>
+#include <Common/typeid_cast.h>
+#include <common/DateLUT.h>
+#include <DataTypes/DataTypeFactory.h>
 #include <Formats/FormatSettings.h>
 #include <Formats/ProtobufReader.h>
 #include <Formats/ProtobufWriter.h>
-#include <DataTypes/DataTypeDateTime.h>
-#include <DataTypes/DataTypeFactory.h>
-
-#include <IO/WriteBufferFromString.h>
 #include <IO/Operators.h>
-
+#include <IO/ReadHelpers.h>
+#include <IO/WriteBufferFromString.h>
+#include <IO/WriteHelpers.h>
+#include <IO/parseDateTimeBestEffort.h>
 #include <Parsers/ASTLiteral.h>
 
-
-namespace DB
+namespace
 {
-
-DataTypeDateTime::DataTypeDateTime(const std::string & time_zone_name)
-    : has_explicit_time_zone(!time_zone_name.empty()),
-    time_zone(DateLUT::instance(time_zone_name)),
-    utc_time_zone(DateLUT::instance("UTC"))
-{
-}
-
-std::string DataTypeDateTime::doGetName() const
-{
-    if (!has_explicit_time_zone)
-        return "DateTime";
-
-    WriteBufferFromOwnString out;
-    out << "DateTime(" << quote << time_zone.getTimeZone() << ")";
-    return out.str();
-}
-
-void DataTypeDateTime::serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const
-{
-    writeDateTimeText(assert_cast<const ColumnUInt32 &>(column).getData()[row_num], ostr, time_zone);
-}
-
-void DataTypeDateTime::serializeTextEscaped(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
-{
-    serializeText(column, row_num, ostr, settings);
-}
-
-
+using namespace DB;
 static inline void readText(time_t & x, ReadBuffer & istr, const FormatSettings & settings, const DateLUTImpl & time_zone, const DateLUTImpl & utc_time_zone)
 {
     switch (settings.date_time_input_format)
@@ -61,7 +32,45 @@ static inline void readText(time_t & x, ReadBuffer & istr, const FormatSettings
             return;
     }
 }
+}
 
+namespace DB
+{
+
+TimezoneMixin::TimezoneMixin(const String & time_zone_name)
+    : has_explicit_time_zone(!time_zone_name.empty()),
+    time_zone(DateLUT::instance(time_zone_name)),
+    utc_time_zone(DateLUT::instance("UTC"))
+{}
+
+DataTypeDateTime::DataTypeDateTime(const String & time_zone_name)
+    : TimezoneMixin(time_zone_name)
+{
+}
+
+DataTypeDateTime::DataTypeDateTime(const TimezoneMixin & time_zone_)
+    : TimezoneMixin(time_zone_)
+{}
+
+String DataTypeDateTime::doGetName() const
+{
+    if (!has_explicit_time_zone)
+        return "DateTime";
+
+    WriteBufferFromOwnString out;
+    out << "DateTime(" << quote << time_zone.getTimeZone() << ")";
+    return out.str();
+}
+
+void DataTypeDateTime::serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const
+{
+    writeDateTimeText(assert_cast<const ColumnType &>(column).getData()[row_num], ostr, time_zone);
+}
+
+void DataTypeDateTime::serializeTextEscaped(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
+{
+    serializeText(column, row_num, ostr, settings);
+}
 
 void DataTypeDateTime::deserializeWholeText(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
 {
@@ -71,8 +80,8 @@ void DataTypeDateTime::deserializeWholeText(IColumn & column, ReadBuffer & istr,
 void DataTypeDateTime::deserializeTextEscaped(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
 {
     time_t x;
-    readText(x, istr, settings, time_zone, utc_time_zone);
-    assert_cast<ColumnUInt32 &>(column).getData().push_back(x);
+    ::readText(x, istr, settings, time_zone, utc_time_zone);
+    assert_cast<ColumnType &>(column).getData().push_back(x);
 }
 
 void DataTypeDateTime::serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
@@ -87,14 +96,14 @@ void DataTypeDateTime::deserializeTextQuoted(IColumn & column, ReadBuffer & istr
     time_t x;
     if (checkChar('\'', istr)) /// Cases: '2017-08-31 18:36:48' or '1504193808'
     {
-        readText(x, istr, settings, time_zone, utc_time_zone);
+        ::readText(x, istr, settings, time_zone, utc_time_zone);
         assertChar('\'', istr);
     }
     else /// Just 1504193808 or 01504193808
     {
         readIntText(x, istr);
     }
-    assert_cast<ColumnUInt32 &>(column).getData().push_back(x);    /// It's important to do this at the end - for exception safety.
+    assert_cast<ColumnType &>(column).getData().push_back(x);    /// It's important to do this at the end - for exception safety.
 }
 
 void DataTypeDateTime::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
@@ -109,14 +118,14 @@ void DataTypeDateTime::deserializeTextJSON(IColumn & column, ReadBuffer & istr,
     time_t x;
     if (checkChar('"', istr))
     {
-        readText(x, istr, settings, time_zone, utc_time_zone);
+        ::readText(x, istr, settings, time_zone, utc_time_zone);
         assertChar('"', istr);
     }
     else
     {
         readIntText(x, istr);
     }
-    assert_cast<ColumnUInt32 &>(column).getData().push_back(x);
+    assert_cast<ColumnType &>(column).getData().push_back(x);
 }
 
 void DataTypeDateTime::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
@@ -138,19 +147,21 @@ void DataTypeDateTime::deserializeTextCSV(IColumn & column, ReadBuffer & istr, c
     if (maybe_quote == '\'' || maybe_quote == '\"')
         ++istr.position();
 
-    readText(x, istr, settings, time_zone, utc_time_zone);
+    ::readText(x, istr, settings, time_zone, utc_time_zone);
 
     if (maybe_quote == '\'' || maybe_quote == '\"')
         assertChar(maybe_quote, istr);
 
-    assert_cast<ColumnUInt32 &>(column).getData().push_back(x);
+    assert_cast<ColumnType &>(column).getData().push_back(x);
 }
 
 void DataTypeDateTime::serializeProtobuf(const IColumn & column, size_t row_num, ProtobufWriter & protobuf, size_t & value_index) const
 {
     if (value_index)
         return;
-    value_index = static_cast<bool>(protobuf.writeDateTime(assert_cast<const ColumnUInt32 &>(column).getData()[row_num]));
+
+    // On some platforms `time_t` is `long` but not `unsigned int` (UInt32 that we store in column), hence static_cast.
+    value_index = static_cast<bool>(protobuf.writeDateTime(static_cast<time_t>(assert_cast<const ColumnType &>(column).getData()[row_num])));
 }
 
 void DataTypeDateTime::deserializeProtobuf(IColumn & column, ProtobufReader & protobuf, bool allow_add_row, bool & row_added) const
@@ -160,7 +171,7 @@ void DataTypeDateTime::deserializeProtobuf(IColumn & column, ProtobufReader & pr
     if (!protobuf.readDateTime(t))
         return;
 
-    auto & container = assert_cast<ColumnUInt32 &>(column).getData();
+    auto & container = assert_cast<ColumnType &>(column).getData();
     if (allow_add_row)
     {
         container.emplace_back(t);
@@ -177,7 +188,6 @@ bool DataTypeDateTime::equals(const IDataType & rhs) const
     return typeid(rhs) == typeid(*this);
 }
 
-
 namespace ErrorCodes
 {
     extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
@@ -205,5 +215,4 @@ void registerDataTypeDateTime(DataTypeFactory & factory)
     factory.registerAlias("TIMESTAMP", "DateTime", DataTypeFactory::CaseInsensitive);
 }
 
-
 }

dbms/src/DataTypes/DataTypeDateTime.h

@@ -1,13 +1,31 @@
 #pragma once
 
+#include <Core/Types.h>
 #include <DataTypes/DataTypeNumberBase.h>
 
-
 class DateLUTImpl;
 
 namespace DB
 {
 
+/** Mixin-class that manages timezone info for timezone-aware DateTime implementations
+ *
+ * Must be used as a (second) base for class implementing IDateType-interface.
+ */
+class TimezoneMixin
+{
+public:
+    explicit TimezoneMixin(const String & time_zone_name = "");
+    TimezoneMixin(const TimezoneMixin &) = default;
+
+    const DateLUTImpl & getTimeZone() const { return time_zone; }
+
+protected:
+    bool has_explicit_time_zone;
+    const DateLUTImpl & time_zone;
+    const DateLUTImpl & utc_time_zone;
+};
+
 /** DateTime stores time as unix timestamp.
   * The value itself is independent of time zone.
   *
@@ -15,7 +33,7 @@ namespace DB
   * In text format it is serialized to and parsed from YYYY-MM-DD hh:mm:ss format.
   * The text format is dependent of time zone.
   *
-  * To convert from/to text format, time zone may be specified explicitly or implicit time zone may be used.
+  * To cast from/to text format, time zone may be specified explicitly or implicit time zone may be used.
   *
   * Time zone may be specified explicitly as type parameter, example: DateTime('Europe/Moscow').
   * As it does not affect the internal representation of values,
@@ -28,13 +46,16 @@ namespace DB
   * Server time zone is the time zone specified in 'timezone' parameter in configuration file,
   *  or system time zone at the moment of server startup.
   */
-class DataTypeDateTime final : public DataTypeNumberBase<UInt32>
+class DataTypeDateTime final : public DataTypeNumberBase<UInt32>, public TimezoneMixin
 {
 public:
-    DataTypeDateTime(const std::string & time_zone_name = "");
+    explicit DataTypeDateTime(const String & time_zone_name = "");
+    explicit DataTypeDateTime(const TimezoneMixin & time_zone);
 
-    const char * getFamilyName() const override { return "DateTime"; }
-    std::string doGetName() const override;
+    static constexpr auto family_name = "DateTime";
+
+    const char * getFamilyName() const override { return family_name; }
+    String doGetName() const override;
     TypeIndex getTypeId() const override { return TypeIndex::DateTime; }
 
     void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override;
@@ -54,13 +75,7 @@ public:
     bool canBeInsideNullable() const override { return true; }
 
     bool equals(const IDataType & rhs) const override;
-
-    const DateLUTImpl & getTimeZone() const { return time_zone; }
-
-private:
-    bool has_explicit_time_zone;
-    const DateLUTImpl & time_zone;
-    const DateLUTImpl & utc_time_zone;
 };
 
 }
+

dbms/src/DataTypes/DataTypeDateTime64.cpp

@@ -0,0 +1,252 @@
+#include <DataTypes/DataTypeDateTime64.h>
+
+#include <Columns/ColumnDecimal.h>
+#include <Columns/ColumnVector.h>
+#include <Columns/ColumnsNumber.h>
+#include <Common/assert_cast.h>
+#include <Common/typeid_cast.h>
+#include <common/DateLUT.h>
+#include <DataTypes/DataTypeFactory.h>
+#include <Formats/FormatSettings.h>
+#include <Formats/ProtobufReader.h>
+#include <Formats/ProtobufWriter.h>
+#include <IO/Operators.h>
+#include <IO/ReadHelpers.h>
+#include <IO/WriteBufferFromString.h>
+#include <IO/WriteHelpers.h>
+#include <IO/parseDateTimeBestEffort.h>
+#include <Parsers/ASTLiteral.h>
+
+#include <optional>
+#include <string>
+
+namespace DB
+{
+
+DataTypeDateTime64::DataTypeDateTime64(UInt32 scale_, const std::string & time_zone_name)
+    : DataTypeDecimalBase<DateTime64>(DecimalUtils::maxPrecision<DateTime64>(), scale_),
+      TimezoneMixin(time_zone_name)
+{
+}
+
+DataTypeDateTime64::DataTypeDateTime64(UInt32 scale_, const TimezoneMixin & time_zone_info)
+    : DataTypeDecimalBase<DateTime64>(DecimalUtils::maxPrecision<DateTime64>() - scale_, scale_),
+      TimezoneMixin(time_zone_info)
+{}
+
+std::string DataTypeDateTime64::doGetName() const
+{
+    if (!has_explicit_time_zone)
+        return std::string(getFamilyName()) + "(" + std::to_string(this->scale) + ")";
+
+    WriteBufferFromOwnString out;
+    out << "DateTime64(" << this->scale << ", " << quote << time_zone.getTimeZone() << ")";
+    return out.str();
+}
+
+void DataTypeDateTime64::serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & /*settings*/) const
+{
+    writeDateTimeText(assert_cast<const ColumnType &>(column).getData()[row_num], scale, ostr, time_zone);
+}
+
+void DataTypeDateTime64::deserializeText(IColumn & column, ReadBuffer & istr, const FormatSettings &) const
+{
+    DateTime64 result = 0;
+    readDateTime64Text(result, this->getScale(), istr, time_zone);
+    assert_cast<ColumnType &>(column).getData().push_back(result);
+}
+
+void DataTypeDateTime64::deserializeWholeText(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
+{
+    deserializeTextEscaped(column, istr, settings);
+}
+
+void DataTypeDateTime64::serializeTextEscaped(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
+{
+    serializeText(column, row_num, ostr, settings);
+}
+
+static inline void readText(DateTime64 & x, UInt32 scale, ReadBuffer & istr, const FormatSettings & settings, const DateLUTImpl & time_zone, const DateLUTImpl & utc_time_zone)
+{
+    switch (settings.date_time_input_format)
+    {
+        case FormatSettings::DateTimeInputFormat::Basic:
+            readDateTime64Text(x, scale, istr, time_zone);
+            return;
+        case FormatSettings::DateTimeInputFormat::BestEffort:
+            parseDateTime64BestEffort(x, scale, istr, time_zone, utc_time_zone);
+            return;
+    }
+}
+
+void DataTypeDateTime64::deserializeTextEscaped(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
+{
+    DateTime64 x = 0;
+    readText(x, scale, istr, settings, time_zone, utc_time_zone);
+    assert_cast<ColumnType &>(column).getData().push_back(x);
+}
+
+void DataTypeDateTime64::serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
+{
+    writeChar('\'', ostr);
+    serializeText(column, row_num, ostr, settings);
+    writeChar('\'', ostr);
+}
+
+void DataTypeDateTime64::deserializeTextQuoted(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
+{
+    DateTime64 x = 0;
+    if (checkChar('\'', istr)) /// Cases: '2017-08-31 18:36:48' or '1504193808'
+    {
+        readText(x, scale, istr, settings, time_zone, utc_time_zone);
+        assertChar('\'', istr);
+    }
+    else /// Just 1504193808 or 01504193808
+    {
+        readIntText(x, istr);
+    }
+    assert_cast<ColumnType &>(column).getData().push_back(x);    /// It's important to do this at the end - for exception safety.
+}
+
+void DataTypeDateTime64::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
+{
+    writeChar('"', ostr);
+    serializeText(column, row_num, ostr, settings);
+    writeChar('"', ostr);
+}
+
+void DataTypeDateTime64::deserializeTextJSON(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
+{
+    DateTime64 x = 0;
+    if (checkChar('"', istr))
+    {
+        readText(x, scale, istr, settings, time_zone, utc_time_zone);
+        assertChar('"', istr);
+    }
+    else
+    {
+        readIntText(x, istr);
+    }
+    assert_cast<ColumnType &>(column).getData().push_back(x);
+}
+
+void DataTypeDateTime64::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings & settings) const
+{
+    writeChar('"', ostr);
+    serializeText(column, row_num, ostr, settings);
+    writeChar('"', ostr);
+}
+
+void DataTypeDateTime64::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
+{
+    DateTime64 x = 0;
+
+    if (istr.eof())
+        throwReadAfterEOF();
+
+    char maybe_quote = *istr.position();
+
+    if (maybe_quote == '\'' || maybe_quote == '\"')
+        ++istr.position();
+
+    readText(x, scale, istr, settings, time_zone, utc_time_zone);
+
+    if (maybe_quote == '\'' || maybe_quote == '\"')
+        assertChar(maybe_quote, istr);
+
+    assert_cast<ColumnType &>(column).getData().push_back(x);
+}
+
+void DataTypeDateTime64::serializeProtobuf(const IColumn & column, size_t row_num, ProtobufWriter & protobuf, size_t & value_index) const
+{
+    if (value_index)
+        return;
+    value_index = static_cast<bool>(protobuf.writeDateTime64(assert_cast<const ColumnType &>(column).getData()[row_num], scale));
+}
+
+void DataTypeDateTime64::deserializeProtobuf(IColumn & column, ProtobufReader & protobuf, bool allow_add_row, bool & row_added) const
+{
+    row_added = false;
+    DateTime64 t = 0;
+    if (!protobuf.readDateTime64(t, scale))
+        return;
+
+    auto & container = assert_cast<ColumnType &>(column).getData();
+    if (allow_add_row)
+    {
+        container.emplace_back(t);
+        row_added = true;
+    }
+    else
+        container.back() = t;
+}
+
+bool DataTypeDateTime64::equals(const IDataType & rhs) const
+{
+    if (auto * ptype = typeid_cast<const DataTypeDateTime64 *>(&rhs))
+        return this->scale == ptype->getScale();
+    return false;
+}
+
+namespace ErrorCodes
+{
+    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
+    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
+}
+
+enum class ArgumentKind
+{
+    Optional,
+    Mandatory
+};
+
+template <typename T, ArgumentKind Kind>
+std::conditional_t<Kind == ArgumentKind::Optional, std::optional<T>, T>
+getArgument(const ASTPtr & arguments, size_t argument_index, const char * argument_name, const std::string context_data_type_name)
+{
+    using NearestResultType = NearestFieldType<T>;
+    const auto fieldType = Field::TypeToEnum<NearestResultType>::value;
+    const ASTLiteral * argument = nullptr;
+
+    auto exceptionMessage = [=](const String & message)
+    {
+        return std::string("Parameter #") + std::to_string(argument_index) + " '"
+                + argument_name + "' for " + context_data_type_name
+                + message
+                + ", expected: " + Field::Types::toString(fieldType) + " literal.";
+    };
+
+    if (!arguments || arguments->children.size() <= argument_index
+        || !(argument = arguments->children[argument_index]->as<ASTLiteral>()))
+    {
+        if constexpr (Kind == ArgumentKind::Optional)
+            return {};
+        else
+            throw Exception(exceptionMessage(" is missing"),
+                            ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
+    }
+
+    if (argument->value.getType() != fieldType)
+        throw Exception(exceptionMessage(String(" has wrong type: ") + argument->value.getTypeName()),
+                        ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
+
+    return argument->value.get<NearestResultType>();
+}
+
+static DataTypePtr create64(const ASTPtr & arguments)
+{
+    if (!arguments || arguments->size() == 0)
+        return std::make_shared<DataTypeDateTime64>(DataTypeDateTime64::default_scale);
+
+    const auto scale = getArgument<UInt64, ArgumentKind::Optional>(arguments, 0, "scale", "DateType64");
+    const auto timezone = getArgument<String, ArgumentKind::Optional>(arguments, !!scale, "timezone", "DateType64");
+
+    return std::make_shared<DataTypeDateTime64>(scale.value_or(DataTypeDateTime64::default_scale), timezone.value_or(String{}));
+}
+
+void registerDataTypeDateTime64(DataTypeFactory & factory)
+{
+    factory.registerDataType("DateTime64", create64, DataTypeFactory::CaseInsensitive);
+}
+
+}

dbms/src/DataTypes/DataTypeDateTime64.h

@@ -0,0 +1,84 @@
+#pragma once
+
+#include <Core/Types.h>
+#include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDecimalBase.h>
+
+class DateLUTImpl;
+
+namespace DB
+{
+
+/** DateTime64 is same as DateTime, but it stores values as Int64 and has configurable sub-second part.
+ *
+ * `scale` determines number of decimal places for sub-second part of the DateTime64.
+  */
+class DataTypeDateTime64 final : public DataTypeDecimalBase<DateTime64>, public TimezoneMixin
+{
+public:
+    static constexpr UInt8 default_scale = 3;
+    static constexpr auto family_name = "DateTime64";
+
+    explicit DataTypeDateTime64(UInt32 scale_, const std::string & time_zone_name = "");
+
+    // reuse timezone from other DateTime/DateTime64
+    DataTypeDateTime64(UInt32 scale_, const TimezoneMixin & time_zone_info);
+
+    const char * getFamilyName() const override { return family_name; }
+    std::string doGetName() const override;
+    TypeIndex getTypeId() const override { return TypeIndex::DateTime64; }
+
+    void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override;
+    void deserializeText(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override;
+    void deserializeWholeText(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const override;
+    void serializeTextEscaped(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override;
+    void deserializeTextEscaped(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override;
+    void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override;
+    void deserializeTextQuoted(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override;
+    void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override;
+    void deserializeTextJSON(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override;
+    void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override;
+    void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const override;
+    void serializeProtobuf(const IColumn & column, size_t row_num, ProtobufWriter & protobuf, size_t & value_index) const override;
+    void deserializeProtobuf(IColumn & column, ProtobufReader & protobuf, bool allow_add_row, bool & row_added) const override;
+
+    bool equals(const IDataType & rhs) const override;
+};
+
+
+/** Basic wrapper for Tansform-types for DateTime64.
+ *
+ * Allows reusing existing Transform (that takes DateTime-values as UInt32) with DateTime64-values,
+ * by discarding fractional part and producing SAME return type as original Transform.
+ *
+ * Such Transfotm-types are commonly used in Date/DateTime manipulation functions,
+ * and implement static execute fucntion with following signature:
+ *      R execute(UInt32, T, const DateLUTImpl &)
+ *
+ * Wehere R and T could be arbitrary types.
+*/
+template <typename Transform>
+class DateTime64BasicTransformWrapper : public Transform
+{
+public:
+    using Transform::execute;
+
+    explicit DateTime64BasicTransformWrapper(UInt32 scale_)
+        : scale_multiplier(DecimalUtils::scaleMultiplier<DateTime64::NativeType>(scale_))
+    {}
+
+    template <typename T>
+    auto execute(DateTime64 t, T v, const DateLUTImpl & time_zone) const
+    {
+        const auto components = DecimalUtils::splitWithScaleMultiplier(t, scale_multiplier);
+        return static_cast<const Transform *>(this)->execute(
+            static_cast<UInt32>(components.whole), v, time_zone);
+    }
+
+private:
+    UInt32 scale_multiplier = 1;
+};
+
+
+}
+

dbms/src/DataTypes/DataTypeDecimalBase.cpp

@@ -0,0 +1,109 @@
+#include <DataTypes/DataTypeDecimalBase.h>
+
+#include <Common/assert_cast.h>
+#include <Common/typeid_cast.h>
+#include <Core/DecimalFunctions.h>
+#include <DataTypes/DataTypeFactory.h>
+#include <Formats/ProtobufReader.h>
+#include <Formats/ProtobufWriter.h>
+#include <IO/ReadHelpers.h>
+#include <IO/WriteHelpers.h>
+#include <IO/readDecimalText.h>
+#include <Interpreters/Context.h>
+#include <Parsers/ASTLiteral.h>
+#include <Parsers/IAST.h>
+
+#include <type_traits>
+
+namespace DB
+{
+
+namespace ErrorCodes
+{
+    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
+    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
+    extern const int ARGUMENT_OUT_OF_BOUND;
+}
+
+
+bool decimalCheckComparisonOverflow(const Context & context) { return context.getSettingsRef().decimal_check_overflow; }
+bool decimalCheckArithmeticOverflow(const Context & context) { return context.getSettingsRef().decimal_check_overflow; }
+
+template <typename T>
+Field DataTypeDecimalBase<T>::getDefault() const
+{
+    return DecimalField(T(0), scale);
+}
+
+template <typename T>
+MutableColumnPtr DataTypeDecimalBase<T>::createColumn() const
+{
+    return ColumnType::create(0, scale);
+}
+
+template <typename T>
+void DataTypeDecimalBase<T>::serializeBinary(const Field & field, WriteBuffer & ostr) const
+{
+    FieldType x = get<DecimalField<T>>(field);
+    writeBinary(x, ostr);
+}
+
+template <typename T>
+void DataTypeDecimalBase<T>::serializeBinary(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
+{
+    const FieldType & x = assert_cast<const ColumnType &>(column).getElement(row_num);
+    writeBinary(x, ostr);
+}
+
+template <typename T>
+void DataTypeDecimalBase<T>::serializeBinaryBulk(const IColumn & column, WriteBuffer & ostr, size_t offset, size_t limit) const
+{
+    const typename ColumnType::Container & x = typeid_cast<const ColumnType &>(column).getData();
+
+    size_t size = x.size();
+
+    if (limit == 0 || offset + limit > size)
+        limit = size - offset;
+
+    ostr.write(reinterpret_cast<const char *>(&x[offset]), sizeof(FieldType) * limit);
+}
+
+template <typename T>
+void DataTypeDecimalBase<T>::deserializeBinary(Field & field, ReadBuffer & istr) const
+{
+    typename FieldType::NativeType x;
+    readBinary(x, istr);
+    field = DecimalField(T(x), this->scale);
+}
+
+template <typename T>
+void DataTypeDecimalBase<T>::deserializeBinary(IColumn & column, ReadBuffer & istr) const
+{
+    typename FieldType::NativeType x;
+    readBinary(x, istr);
+    assert_cast<ColumnType &>(column).getData().push_back(FieldType(x));
+}
+
+template <typename T>
+void DataTypeDecimalBase<T>::deserializeBinaryBulk(IColumn & column, ReadBuffer & istr, size_t limit, double) const
+{
+    typename ColumnType::Container & x = typeid_cast<ColumnType &>(column).getData();
+    size_t initial_size = x.size();
+    x.resize(initial_size + limit);
+    size_t size = istr.readBig(reinterpret_cast<char*>(&x[initial_size]), sizeof(FieldType) * limit);
+    x.resize(initial_size + size / sizeof(FieldType));
+}
+
+template <typename T>
+T DataTypeDecimalBase<T>::getScaleMultiplier(UInt32 scale_)
+{
+    return DecimalUtils::scaleMultiplier<typename T::NativeType>(scale_);
+}
+
+
+/// Explicit template instantiations.
+template class DataTypeDecimalBase<Decimal32>;
+template class DataTypeDecimalBase<Decimal64>;
+template class DataTypeDecimalBase<Decimal128>;
+
+}

dbms/src/DataTypes/DataTypeDecimalBase.h

@@ -0,0 +1,213 @@
+#pragma once
+#include <cmath>
+
+#include <common/likely.h>
+#include <Columns/ColumnDecimal.h>
+#include <Core/DecimalFunctions.h>
+#include <DataTypes/IDataType.h>
+#include <DataTypes/DataTypesNumber.h>
+#include <DataTypes/DataTypeWithSimpleSerialization.h>
+
+#include <type_traits>
+
+
+namespace DB
+{
+
+namespace ErrorCodes
+{
+    extern const int ARGUMENT_OUT_OF_BOUND;
+    extern const int CANNOT_CONVERT_TYPE;
+    extern const int DECIMAL_OVERFLOW;
+}
+
+class Context;
+bool decimalCheckComparisonOverflow(const Context & context);
+bool decimalCheckArithmeticOverflow(const Context & context);
+
+inline UInt32 leastDecimalPrecisionFor(TypeIndex int_type)
+{
+    switch (int_type)
+    {
+        case TypeIndex::Int8: [[fallthrough]];
+        case TypeIndex::UInt8:
+            return 3;
+        case TypeIndex::Int16: [[fallthrough]];
+        case TypeIndex::UInt16:
+            return 5;
+        case TypeIndex::Int32: [[fallthrough]];
+        case TypeIndex::UInt32:
+            return 10;
+        case TypeIndex::Int64:
+            return 19;
+        case TypeIndex::UInt64:
+            return 20;
+        default:
+            break;
+    }
+    return 0;
+}
+
+/// Base class for decimals, like Decimal(P, S), where P is precision, S is scale.
+/// Maximum precisions for underlying types are:
+/// Int32    9
+/// Int64   18
+/// Int128  38
+/// Operation between two decimals leads to Decimal(P, S), where
+///     P is one of (9, 18, 38); equals to the maximum precision for the biggest underlying type of operands.
+///     S is maximum scale of operands. The allowed valuas are [0, precision]
+template <typename T>
+class DataTypeDecimalBase : public DataTypeWithSimpleSerialization
+{
+    static_assert(IsDecimalNumber<T>);
+
+public:
+    using FieldType = T;
+    using ColumnType = ColumnDecimal<T>;
+
+    static constexpr bool is_parametric = true;
+
+    static constexpr size_t maxPrecision() { return DecimalUtils::maxPrecision<T>(); }
+
+    DataTypeDecimalBase(UInt32 precision_, UInt32 scale_)
+    :   precision(precision_),
+        scale(scale_)
+    {
+        if (unlikely(precision < 1 || precision > maxPrecision()))
+            throw Exception("Precision " + std::to_string(precision) + " is out of bounds", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
+        if (unlikely(scale < 0 || static_cast<UInt32>(scale) > maxPrecision()))
+            throw Exception("Scale " + std::to_string(scale) + " is out of bounds", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
+    }
+
+    TypeIndex getTypeId() const override { return TypeId<T>::value; }
+
+    Field getDefault() const override;
+    MutableColumnPtr createColumn() const override;
+
+    bool isParametric() const override { return true; }
+    bool haveSubtypes() const override { return false; }
+    bool shouldAlignRightInPrettyFormats() const override { return true; }
+    bool textCanContainOnlyValidUTF8() const override { return true; }
+    bool isComparable() const override { return true; }
+    bool isValueRepresentedByNumber() const override { return true; }
+    bool isValueUnambiguouslyRepresentedInContiguousMemoryRegion() const override { return true; }
+    bool haveMaximumSizeOfValue() const override { return true; }
+    size_t getSizeOfValueInMemory() const override { return sizeof(T); }
+
+    bool isSummable() const override { return true; }
+    bool canBeUsedInBooleanContext() const override { return true; }
+    bool canBeInsideNullable() const override { return true; }
+
+    void serializeBinary(const Field & field, WriteBuffer & ostr) const override;
+    void serializeBinary(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+    void serializeBinaryBulk(const IColumn & column, WriteBuffer & ostr, size_t offset, size_t limit) const override;
+
+    void deserializeBinary(Field & field, ReadBuffer & istr) const override;
+    void deserializeBinary(IColumn & column, ReadBuffer & istr) const override;
+    void deserializeBinaryBulk(IColumn & column, ReadBuffer & istr, size_t limit, double avg_value_size_hint) const override;
+
+    /// Decimal specific
+
+    UInt32 getPrecision() const { return precision; }
+    UInt32 getScale() const { return scale; }
+    T getScaleMultiplier() const { return getScaleMultiplier(scale); }
+
+    T wholePart(T x) const
+    {
+        return DecimalUtils::getWholePart(x, scale);
+    }
+
+    T fractionalPart(T x) const
+    {
+        return DecimalUtils::getFractionalPart(x, scale);
+    }
+
+    T maxWholeValue() const { return getScaleMultiplier(maxPrecision() - scale) - T(1); }
+
+    bool canStoreWhole(T x) const
+    {
+        T max = maxWholeValue();
+        if (x > max || x < -max)
+            return false;
+        return true;
+    }
+
+    /// @returns multiplier for U to become T with correct scale
+    template <typename U>
+    T scaleFactorFor(const DataTypeDecimalBase<U> & x, bool) const
+    {
+        if (getScale() < x.getScale())
+            throw Exception("Decimal result's scale is less than argument's one", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
+        UInt32 scale_delta = getScale() - x.getScale(); /// scale_delta >= 0
+        return getScaleMultiplier(scale_delta);
+    }
+
+    template <typename U>
+    T scaleFactorFor(const DataTypeNumber<U> & , bool is_multiply_or_divisor) const
+    {
+        if (is_multiply_or_divisor)
+            return 1;
+        return getScaleMultiplier();
+    }
+
+    static T getScaleMultiplier(UInt32 scale);
+
+protected:
+    const UInt32 precision;
+    const UInt32 scale;
+};
+
+
+template <typename T, typename U, template <typename> typename DecimalType>
+typename std::enable_if_t<(sizeof(T) >= sizeof(U)), DecimalType<T>>
+decimalResultType(const DecimalType<T> & tx, const DecimalType<U> & ty, bool is_multiply, bool is_divide)
+{
+    UInt32 scale = (tx.getScale() > ty.getScale() ? tx.getScale() : ty.getScale());
+    if (is_multiply)
+        scale = tx.getScale() + ty.getScale();
+    else if (is_divide)
+        scale = tx.getScale();
+    return DecimalType<T>(DecimalUtils::maxPrecision<T>(), scale);
+}
+
+template <typename T, typename U, template <typename> typename DecimalType>
+typename std::enable_if_t<(sizeof(T) < sizeof(U)), const DecimalType<U>>
+decimalResultType(const DecimalType<T> & tx, const DecimalType<U> & ty, bool is_multiply, bool is_divide)
+{
+    UInt32 scale = (tx.getScale() > ty.getScale() ? tx.getScale() : ty.getScale());
+    if (is_multiply)
+        scale = tx.getScale() * ty.getScale();
+    else if (is_divide)
+        scale = tx.getScale();
+    return DecimalType<U>(DecimalUtils::maxPrecision<U>(), scale);
+}
+
+template <typename T, typename U, template <typename> typename DecimalType>
+const DecimalType<T> decimalResultType(const DecimalType<T> & tx, const DataTypeNumber<U> &, bool, bool)
+{
+    return DecimalType<T>(DecimalUtils::maxPrecision<T>(), tx.getScale());
+}
+
+template <typename T, typename U, template <typename> typename DecimalType>
+const DecimalType<U> decimalResultType(const DataTypeNumber<T> &, const DecimalType<U> & ty, bool, bool)
+{
+    return DecimalType<U>(DecimalUtils::maxPrecision<U>(), ty.getScale());
+}
+
+template <template <typename> typename DecimalType>
+DataTypePtr createDecimal(UInt64 precision_value, UInt64 scale_value)
+{
+    if (precision_value < DecimalUtils::minPrecision() || precision_value > DecimalUtils::maxPrecision<Decimal128>())
+        throw Exception("Wrong precision", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
+
+    if (static_cast<UInt64>(scale_value) > precision_value)
+        throw Exception("Negative scales and scales larger than precision are not supported", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
+
+    if (precision_value <= DecimalUtils::maxPrecision<Decimal32>())
+        return std::make_shared<DecimalType<Decimal32>>(precision_value, scale_value);
+    else if (precision_value <= DecimalUtils::maxPrecision<Decimal64>())
+        return std::make_shared<DecimalType<Decimal64>>(precision_value, scale_value);
+    return std::make_shared<DecimalType<Decimal128>>(precision_value, scale_value);
+}
+
+}

dbms/src/DataTypes/DataTypeEnum.cpp

@@ -127,7 +127,7 @@ void DataTypeEnum<Type>::serializeBinary(const IColumn & column, size_t row_num,
 template <typename Type>
 void DataTypeEnum<Type>::deserializeBinary(IColumn & column, ReadBuffer & istr) const
 {
-    typename ColumnType::value_type x;
+    typename ColumnType::ValueType x;
     readBinary(x, istr);
     assert_cast<ColumnType &>(column).getData().push_back(x);
 }

dbms/src/DataTypes/DataTypeFactory.cpp

@@ -161,6 +161,7 @@ void registerDataTypeNumbers(DataTypeFactory & factory);
 void registerDataTypeDecimal(DataTypeFactory & factory);
 void registerDataTypeDate(DataTypeFactory & factory);
 void registerDataTypeDateTime(DataTypeFactory & factory);
+void registerDataTypeDateTime64(DataTypeFactory & factory);
 void registerDataTypeString(DataTypeFactory & factory);
 void registerDataTypeFixedString(DataTypeFactory & factory);
 void registerDataTypeEnum(DataTypeFactory & factory);
@@ -183,6 +184,7 @@ DataTypeFactory::DataTypeFactory()
     registerDataTypeDecimal(*this);
     registerDataTypeDate(*this);
     registerDataTypeDateTime(*this);
+    registerDataTypeDateTime64(*this);
     registerDataTypeString(*this);
     registerDataTypeFixedString(*this);
     registerDataTypeEnum(*this);

dbms/src/DataTypes/DataTypeNumberBase.cpp

@@ -153,15 +153,15 @@ Field DataTypeNumberBase<T>::getDefault() const
 template <typename T>
 void DataTypeNumberBase<T>::serializeBinary(const Field & field, WriteBuffer & ostr) const
 {
-    /// ColumnVector<T>::value_type is a narrower type. For example, UInt8, when the Field type is UInt64
-    typename ColumnVector<T>::value_type x = get<NearestFieldType<FieldType>>(field);
+    /// ColumnVector<T>::ValueType is a narrower type. For example, UInt8, when the Field type is UInt64
+    typename ColumnVector<T>::ValueType x = get<NearestFieldType<FieldType>>(field);
     writeBinary(x, ostr);
 }
 
 template <typename T>
 void DataTypeNumberBase<T>::deserializeBinary(Field & field, ReadBuffer & istr) const
 {
-    typename ColumnVector<T>::value_type x;
+    typename ColumnVector<T>::ValueType x;
     readBinary(x, istr);
     field = NearestFieldType<FieldType>(x);
 }
@@ -175,7 +175,7 @@ void DataTypeNumberBase<T>::serializeBinary(const IColumn & column, size_t row_n
 template <typename T>
 void DataTypeNumberBase<T>::deserializeBinary(IColumn & column, ReadBuffer & istr) const
 {
-    typename ColumnVector<T>::value_type x;
+    typename ColumnVector<T>::ValueType x;
     readBinary(x, istr);
     assert_cast<ColumnVector<T> &>(column).getData().push_back(x);
 }
@@ -191,7 +191,7 @@ void DataTypeNumberBase<T>::serializeBinaryBulk(const IColumn & column, WriteBuf
         limit = size - offset;
 
     if (limit)
-        ostr.write(reinterpret_cast<const char *>(&x[offset]), sizeof(typename ColumnVector<T>::value_type) * limit);
+        ostr.write(reinterpret_cast<const char *>(&x[offset]), sizeof(typename ColumnVector<T>::ValueType) * limit);
 }
 
 template <typename T>
@@ -200,8 +200,8 @@ void DataTypeNumberBase<T>::deserializeBinaryBulk(IColumn & column, ReadBuffer &
     typename ColumnVector<T>::Container & x = typeid_cast<ColumnVector<T> &>(column).getData();
     size_t initial_size = x.size();
     x.resize(initial_size + limit);
-    size_t size = istr.readBig(reinterpret_cast<char*>(&x[initial_size]), sizeof(typename ColumnVector<T>::value_type) * limit);
-    x.resize(initial_size + size / sizeof(typename ColumnVector<T>::value_type));
+    size_t size = istr.readBig(reinterpret_cast<char*>(&x[initial_size]), sizeof(typename ColumnVector<T>::ValueType) * limit);
+    x.resize(initial_size + size / sizeof(typename ColumnVector<T>::ValueType));
 }
 
 

dbms/src/DataTypes/DataTypeNumberBase.h

@@ -7,6 +7,9 @@
 namespace DB
 {
 
+template <typename T>
+class ColumnVector;
+
 /** Implements part of the IDataType interface, common to all numbers and for Date and DateTime.
   */
 template <typename T>
@@ -18,6 +21,8 @@ public:
     static constexpr bool is_parametric = false;
     using FieldType = T;
 
+    using ColumnType = ColumnVector<T>;
+
     const char * getFamilyName() const override { return TypeName<T>::get(); }
     TypeIndex getTypeId() const override { return TypeId<T>::value; }
 

dbms/src/DataTypes/DataTypesDecimal.cpp

@@ -1,17 +1,19 @@
-#include <type_traits>
-#include <Common/typeid_cast.h>
-#include <Common/assert_cast.h>
 #include <DataTypes/DataTypesDecimal.h>
+
+#include <Common/assert_cast.h>
+#include <Common/typeid_cast.h>
+#include <Core/DecimalFunctions.h>
 #include <DataTypes/DataTypeFactory.h>
 #include <Formats/ProtobufReader.h>
 #include <Formats/ProtobufWriter.h>
 #include <IO/ReadHelpers.h>
 #include <IO/WriteHelpers.h>
 #include <IO/readDecimalText.h>
-#include <Parsers/IAST.h>
-#include <Parsers/ASTLiteral.h>
 #include <Interpreters/Context.h>
+#include <Parsers/ASTLiteral.h>
+#include <Parsers/IAST.h>
 
+#include <type_traits>
 
 namespace DB
 {
@@ -23,34 +25,38 @@ namespace ErrorCodes
     extern const int ARGUMENT_OUT_OF_BOUND;
 }
 
-
-bool decimalCheckComparisonOverflow(const Context & context) { return context.getSettingsRef().decimal_check_overflow; }
-bool decimalCheckArithmeticOverflow(const Context & context) { return context.getSettingsRef().decimal_check_overflow; }
-
-
 //
 
 template <typename T>
 std::string DataTypeDecimal<T>::doGetName() const
 {
     std::stringstream ss;
-    ss << "Decimal(" << precision << ", " << scale << ")";
+    ss << "Decimal(" << this->precision << ", " << this->scale << ")";
     return ss.str();
 }
 
+
+
 template <typename T>
 bool DataTypeDecimal<T>::equals(const IDataType & rhs) const
 {
     if (auto * ptype = typeid_cast<const DataTypeDecimal<T> *>(&rhs))
-        return scale == ptype->getScale();
+        return this->scale == ptype->getScale();
     return false;
 }
 
+template <typename T>
+DataTypePtr DataTypeDecimal<T>::promoteNumericType() const
+{
+    using PromotedType = DataTypeDecimal<Decimal128>;
+    return std::make_shared<PromotedType>(PromotedType::maxPrecision(), this->scale);
+}
+
 template <typename T>
 void DataTypeDecimal<T>::serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const
 {
     T value = assert_cast<const ColumnType &>(column).getData()[row_num];
-    writeText(value, scale, ostr);
+    writeText(value, this->scale, ostr);
 }
 
 template <typename T>
@@ -58,6 +64,7 @@ bool DataTypeDecimal<T>::tryReadText(T & x, ReadBuffer & istr, UInt32 precision,
 {
     UInt32 unread_scale = scale;
     bool done = tryReadDecimalText(istr, x, precision, unread_scale);
+
     x *= T::getScaleMultiplier(unread_scale);
     return done;
 }
@@ -94,74 +101,19 @@ T DataTypeDecimal<T>::parseFromString(const String & str) const
 {
     ReadBufferFromMemory buf(str.data(), str.size());
     T x;
-    UInt32 unread_scale = scale;
-    readDecimalText(buf, x, precision, unread_scale, true);
+    UInt32 unread_scale = this->scale;
+    readDecimalText(buf, x, this->precision, unread_scale, true);
     x *= T::getScaleMultiplier(unread_scale);
+
     return x;
 }
 
-
-template <typename T>
-void DataTypeDecimal<T>::serializeBinary(const Field & field, WriteBuffer & ostr) const
-{
-    FieldType x = get<DecimalField<T>>(field);
-    writeBinary(x, ostr);
-}
-
-template <typename T>
-void DataTypeDecimal<T>::serializeBinary(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
-{
-    const FieldType & x = assert_cast<const ColumnType &>(column).getElement(row_num);
-    writeBinary(x, ostr);
-}
-
-template <typename T>
-void DataTypeDecimal<T>::serializeBinaryBulk(const IColumn & column, WriteBuffer & ostr, size_t offset, size_t limit) const
-{
-    const typename ColumnType::Container & x = typeid_cast<const ColumnType &>(column).getData();
-
-    size_t size = x.size();
-
-    if (limit == 0 || offset + limit > size)
-        limit = size - offset;
-
-    ostr.write(reinterpret_cast<const char *>(&x[offset]), sizeof(FieldType) * limit);
-}
-
-
-template <typename T>
-void DataTypeDecimal<T>::deserializeBinary(Field & field, ReadBuffer & istr) const
-{
-    typename FieldType::NativeType x;
-    readBinary(x, istr);
-    field = DecimalField(T(x), scale);
-}
-
-template <typename T>
-void DataTypeDecimal<T>::deserializeBinary(IColumn & column, ReadBuffer & istr) const
-{
-    typename FieldType::NativeType x;
-    readBinary(x, istr);
-    assert_cast<ColumnType &>(column).getData().push_back(FieldType(x));
-}
-
-template <typename T>
-void DataTypeDecimal<T>::deserializeBinaryBulk(IColumn & column, ReadBuffer & istr, size_t limit, double) const
-{
-    typename ColumnType::Container & x = typeid_cast<ColumnType &>(column).getData();
-    size_t initial_size = x.size();
-    x.resize(initial_size + limit);
-    size_t size = istr.readBig(reinterpret_cast<char*>(&x[initial_size]), sizeof(FieldType) * limit);
-    x.resize(initial_size + size / sizeof(FieldType));
-}
-
-
 template <typename T>
 void DataTypeDecimal<T>::serializeProtobuf(const IColumn & column, size_t row_num, ProtobufWriter & protobuf, size_t & value_index) const
 {
     if (value_index)
         return;
-    value_index = static_cast<bool>(protobuf.writeDecimal(assert_cast<const ColumnType &>(column).getData()[row_num], scale));
+    value_index = static_cast<bool>(protobuf.writeDecimal(assert_cast<const ColumnType &>(column).getData()[row_num], this->scale));
 }
 
 
@@ -170,7 +122,7 @@ void DataTypeDecimal<T>::deserializeProtobuf(IColumn & column, ProtobufReader &
 {
     row_added = false;
     T decimal;
-    if (!protobuf.readDecimal(decimal, precision, scale))
+    if (!protobuf.readDecimal(decimal, this->precision, this->scale))
         return;
 
     auto & container = assert_cast<ColumnType &>(column).getData();
@@ -184,45 +136,6 @@ void DataTypeDecimal<T>::deserializeProtobuf(IColumn & column, ProtobufReader &
 }
 
 
-template <typename T>
-Field DataTypeDecimal<T>::getDefault() const
-{
-    return DecimalField(T(0), scale);
-}
-
-
-template <typename T>
-DataTypePtr DataTypeDecimal<T>::promoteNumericType() const
-{
-    using PromotedType = DataTypeDecimal<Decimal128>;
-    return std::make_shared<PromotedType>(PromotedType::maxPrecision(), scale);
-}
-
-
-template <typename T>
-MutableColumnPtr DataTypeDecimal<T>::createColumn() const
-{
-    return ColumnType::create(0, scale);
-}
-
-
-//
-
-DataTypePtr createDecimal(UInt64 precision_value, UInt64 scale_value)
-{
-    if (precision_value < minDecimalPrecision() || precision_value > maxDecimalPrecision<Decimal128>())
-        throw Exception("Wrong precision", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
-
-    if (static_cast<UInt64>(scale_value) > precision_value)
-        throw Exception("Negative scales and scales larger than precision are not supported", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
-
-    if (precision_value <= maxDecimalPrecision<Decimal32>())
-        return std::make_shared<DataTypeDecimal<Decimal32>>(precision_value, scale_value);
-    else if (precision_value <= maxDecimalPrecision<Decimal64>())
-        return std::make_shared<DataTypeDecimal<Decimal64>>(precision_value, scale_value);
-    return std::make_shared<DataTypeDecimal<Decimal128>>(precision_value, scale_value);
-}
-
 static DataTypePtr create(const ASTPtr & arguments)
 {
     if (!arguments || arguments->children.size() != 2)
@@ -234,12 +147,12 @@ static DataTypePtr create(const ASTPtr & arguments)
 
     if (!precision || precision->value.getType() != Field::Types::UInt64 ||
         !scale || !(scale->value.getType() == Field::Types::Int64 || scale->value.getType() == Field::Types::UInt64))
-        throw Exception("Decimal data type family must have a two numbers as its arguments", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
+        throw Exception("Decimal data type family must have two numbers as its arguments", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 
     UInt64 precision_value = precision->value.get<UInt64>();
     UInt64 scale_value = scale->value.get<UInt64>();
 
-    return createDecimal(precision_value, scale_value);
+    return createDecimal<DataTypeDecimal>(precision_value, scale_value);
 }
 
 template <typename T>
@@ -254,10 +167,10 @@ static DataTypePtr createExact(const ASTPtr & arguments)
     if (!scale_arg || !(scale_arg->value.getType() == Field::Types::Int64 || scale_arg->value.getType() == Field::Types::UInt64))
         throw Exception("Decimal data type family must have a two numbers as its arguments", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 
-    UInt64 precision = maxDecimalPrecision<T>();
+    UInt64 precision = DecimalUtils::maxPrecision<T>();
     UInt64 scale = scale_arg->value.get<UInt64>();
 
-    return createDecimal(precision, scale);
+    return createDecimal<DataTypeDecimal>(precision, scale);
 }
 
 void registerDataTypeDecimal(DataTypeFactory & factory)
@@ -270,7 +183,6 @@ void registerDataTypeDecimal(DataTypeFactory & factory)
     factory.registerAlias("DEC", "Decimal", DataTypeFactory::CaseInsensitive);
 }
 
-
 /// Explicit template instantiations.
 template class DataTypeDecimal<Decimal32>;
 template class DataTypeDecimal<Decimal64>;

dbms/src/DataTypes/DataTypesDecimal.h

@@ -1,12 +1,9 @@
 #pragma once
-#include <cmath>
 
 #include <common/arithmeticOverflow.h>
 #include <Common/typeid_cast.h>
-#include <Columns/ColumnDecimal.h>
 #include <DataTypes/IDataType.h>
-#include <DataTypes/DataTypesNumber.h>
-#include <DataTypes/DataTypeWithSimpleSerialization.h>
+#include <DataTypes/DataTypeDecimalBase.h>
 
 
 namespace DB
@@ -19,43 +16,6 @@ namespace ErrorCodes
     extern const int DECIMAL_OVERFLOW;
 }
 
-class Context;
-bool decimalCheckComparisonOverflow(const Context & context);
-bool decimalCheckArithmeticOverflow(const Context & context);
-
-
-static constexpr size_t minDecimalPrecision() { return 1; }
-template <typename T> static constexpr size_t maxDecimalPrecision() { return 0; }
-template <> constexpr size_t maxDecimalPrecision<Decimal32>() { return 9; }
-template <> constexpr size_t maxDecimalPrecision<Decimal64>() { return 18; }
-template <> constexpr size_t maxDecimalPrecision<Decimal128>() { return 38; }
-
-
-DataTypePtr createDecimal(UInt64 precision, UInt64 scale);
-
-inline UInt32 leastDecimalPrecisionFor(TypeIndex int_type)
-{
-    switch (int_type)
-    {
-        case TypeIndex::Int8: [[fallthrough]];
-        case TypeIndex::UInt8:
-            return 3;
-        case TypeIndex::Int16: [[fallthrough]];
-        case TypeIndex::UInt16:
-            return 5;
-        case TypeIndex::Int32: [[fallthrough]];
-        case TypeIndex::UInt32:
-            return 10;
-        case TypeIndex::Int64:
-            return 19;
-        case TypeIndex::UInt64:
-            return 20;
-        default:
-            break;
-    }
-    return 0;
-}
-
 /// Implements Decimal(P, S), where P is precision, S is scale.
 /// Maximum precisions for underlying types are:
 /// Int32    9
@@ -65,166 +25,40 @@ inline UInt32 leastDecimalPrecisionFor(TypeIndex int_type)
 ///     P is one of (9, 18, 38); equals to the maximum precision for the biggest underlying type of operands.
 ///     S is maximum scale of operands. The allowed valuas are [0, precision]
 template <typename T>
-class DataTypeDecimal final : public DataTypeWithSimpleSerialization
+class DataTypeDecimal final : public DataTypeDecimalBase<T>
 {
+    using Base = DataTypeDecimalBase<T>;
     static_assert(IsDecimalNumber<T>);
 
 public:
-    using FieldType = T;
-    using ColumnType = ColumnDecimal<T>;
+    using typename Base::FieldType;
+    using typename Base::ColumnType;
+    using Base::Base;
 
-    static constexpr bool is_parametric = true;
+    static constexpr auto family_name = "Decimal";
 
-    static constexpr size_t maxPrecision() { return maxDecimalPrecision<T>(); }
-
-    DataTypeDecimal(UInt32 precision_, UInt32 scale_)
-    :   precision(precision_),
-        scale(scale_)
-    {
-        if (unlikely(precision < 1 || precision > maxPrecision()))
-            throw Exception("Precision " + std::to_string(precision) + " is out of bounds", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
-        if (unlikely(scale < 0 || static_cast<UInt32>(scale) > maxPrecision()))
-            throw Exception("Scale " + std::to_string(scale) + " is out of bounds", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
-    }
-
-    const char * getFamilyName() const override { return "Decimal"; }
+    const char * getFamilyName() const override { return family_name; }
     std::string doGetName() const override;
     TypeIndex getTypeId() const override { return TypeId<T>::value; }
+    bool canBePromoted() const override { return true; }
+    DataTypePtr promoteNumericType() const override;
 
     void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override;
     void deserializeText(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override;
     void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override;
 
-    void serializeBinary(const Field & field, WriteBuffer & ostr) const override;
-    void serializeBinary(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
-    void serializeBinaryBulk(const IColumn & column, WriteBuffer & ostr, size_t offset, size_t limit) const override;
-
-    void deserializeBinary(Field & field, ReadBuffer & istr) const override;
-    void deserializeBinary(IColumn & column, ReadBuffer & istr) const override;
-    void deserializeBinaryBulk(IColumn & column, ReadBuffer & istr, size_t limit, double avg_value_size_hint) const override;
-
     void serializeProtobuf(const IColumn & column, size_t row_num, ProtobufWriter & protobuf, size_t & value_index) const override;
     void deserializeProtobuf(IColumn & column, ProtobufReader & protobuf, bool allow_add_row, bool & row_added) const override;
 
-    Field getDefault() const override;
-    bool canBePromoted() const override { return true; }
-    DataTypePtr promoteNumericType() const override;
-    MutableColumnPtr createColumn() const override;
     bool equals(const IDataType & rhs) const override;
 
-    bool isParametric() const override { return true; }
-    bool haveSubtypes() const override { return false; }
-    bool shouldAlignRightInPrettyFormats() const override { return true; }
-    bool textCanContainOnlyValidUTF8() const override { return true; }
-    bool isComparable() const override { return true; }
-    bool isValueRepresentedByNumber() const override { return true; }
-    bool isValueUnambiguouslyRepresentedInContiguousMemoryRegion() const override { return true; }
-    bool haveMaximumSizeOfValue() const override { return true; }
-    size_t getSizeOfValueInMemory() const override { return sizeof(T); }
-
-    bool isSummable() const override { return true; }
-    bool canBeUsedInBooleanContext() const override { return true; }
-    bool canBeInsideNullable() const override { return true; }
-
-    /// Decimal specific
-
-    UInt32 getPrecision() const { return precision; }
-    UInt32 getScale() const { return scale; }
-    T getScaleMultiplier() const { return T::getScaleMultiplier(scale); }
-
-    T wholePart(T x) const
-    {
-        if (scale == 0)
-            return x;
-        return x / getScaleMultiplier();
-    }
-
-    T fractionalPart(T x) const
-    {
-        if (scale == 0)
-            return 0;
-        if (x < T(0))
-            x *= T(-1);
-        return x % getScaleMultiplier();
-    }
-
-    T maxWholeValue() const { return T::getScaleMultiplier(maxPrecision() - scale) - T(1); }
-
-    bool canStoreWhole(T x) const
-    {
-        T max = maxWholeValue();
-        if (x > max || x < -max)
-            return false;
-        return true;
-    }
-
-    /// @returns multiplier for U to become T with correct scale
-    template <typename U>
-    T scaleFactorFor(const DataTypeDecimal<U> & x, bool) const
-    {
-        if (getScale() < x.getScale())
-            throw Exception("Decimal result's scale is less then argiment's one", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
-        UInt32 scale_delta = getScale() - x.getScale(); /// scale_delta >= 0
-        return T::getScaleMultiplier(scale_delta);
-    }
-
-    template <typename U>
-    T scaleFactorFor(const DataTypeNumber<U> & , bool is_multiply_or_divisor) const
-    {
-        if (is_multiply_or_divisor)
-            return 1;
-        return getScaleMultiplier();
-    }
-
     T parseFromString(const String & str) const;
+    void readText(T & x, ReadBuffer & istr, bool csv = false) const { readText(x, istr, this->precision, this->scale, csv); }
 
-    void readText(T & x, ReadBuffer & istr, bool csv = false) const { readText(x, istr, precision, scale, csv); }
-    static void readText(T & x, ReadBuffer & istr, UInt32 precision, UInt32 scale, bool csv = false);
-    static bool tryReadText(T & x, ReadBuffer & istr, UInt32 precision, UInt32 scale);
-
-private:
-    const UInt32 precision;
-    const UInt32 scale;
+    static void readText(T & x, ReadBuffer & istr, UInt32 precision_, UInt32 scale_, bool csv = false);
+    static bool tryReadText(T & x, ReadBuffer & istr, UInt32 precision_, UInt32 scale_);
 };
 
-
-template <typename T, typename U>
-typename std::enable_if_t<(sizeof(T) >= sizeof(U)), const DataTypeDecimal<T>>
-decimalResultType(const DataTypeDecimal<T> & tx, const DataTypeDecimal<U> & ty, bool is_multiply, bool is_divide)
-{
-    UInt32 scale = (tx.getScale() > ty.getScale() ? tx.getScale() : ty.getScale());
-    if (is_multiply)
-        scale = tx.getScale() + ty.getScale();
-    else if (is_divide)
-        scale = tx.getScale();
-    return DataTypeDecimal<T>(maxDecimalPrecision<T>(), scale);
-}
-
-template <typename T, typename U>
-typename std::enable_if_t<(sizeof(T) < sizeof(U)), const DataTypeDecimal<U>>
-decimalResultType(const DataTypeDecimal<T> & tx, const DataTypeDecimal<U> & ty, bool is_multiply, bool is_divide)
-{
-    UInt32 scale = (tx.getScale() > ty.getScale() ? tx.getScale() : ty.getScale());
-    if (is_multiply)
-        scale = tx.getScale() * ty.getScale();
-    else if (is_divide)
-        scale = tx.getScale();
-    return DataTypeDecimal<U>(maxDecimalPrecision<U>(), scale);
-}
-
-template <typename T, typename U>
-const DataTypeDecimal<T> decimalResultType(const DataTypeDecimal<T> & tx, const DataTypeNumber<U> &, bool, bool)
-{
-    return DataTypeDecimal<T>(maxDecimalPrecision<T>(), tx.getScale());
-}
-
-template <typename T, typename U>
-const DataTypeDecimal<U> decimalResultType(const DataTypeNumber<T> &, const DataTypeDecimal<U> & ty, bool, bool)
-{
-    return DataTypeDecimal<U>(maxDecimalPrecision<U>(), ty.getScale());
-}
-
-
 template <typename T>
 inline const DataTypeDecimal<T> * checkDecimal(const IDataType & data_type)
 {
@@ -242,14 +76,11 @@ inline UInt32 getDecimalScale(const IDataType & data_type, UInt32 default_value
     return default_value;
 }
 
-///
-
-template <typename DataType> constexpr bool IsDataTypeDecimal = false;
-template <> inline constexpr bool IsDataTypeDecimal<DataTypeDecimal<Decimal32>> = true;
-template <> inline constexpr bool IsDataTypeDecimal<DataTypeDecimal<Decimal64>> = true;
-template <> inline constexpr bool IsDataTypeDecimal<DataTypeDecimal<Decimal128>> = true;
-
-template <typename DataType> constexpr bool IsDataTypeDecimalOrNumber = IsDataTypeDecimal<DataType> || IsDataTypeNumber<DataType>;
+template <typename T>
+inline UInt32 getDecimalScale(const DataTypeDecimal<T> & data_type)
+{
+    return data_type.getScale();
+}
 
 template <typename FromDataType, typename ToDataType>
 inline std::enable_if_t<IsDataTypeDecimal<FromDataType> && IsDataTypeDecimal<ToDataType>, typename ToDataType::FieldType>
@@ -265,7 +96,8 @@ convertDecimals(const typename FromDataType::FieldType & value, UInt32 scale_fro
     {
         converted_value = MaxFieldType::getScaleMultiplier(scale_to - scale_from);
         if (common::mulOverflow(static_cast<MaxNativeType>(value), converted_value, converted_value))
-            throw Exception("Decimal convert overflow", ErrorCodes::DECIMAL_OVERFLOW);
+            throw Exception(std::string(ToDataType::family_name) + " convert overflow",
+                            ErrorCodes::DECIMAL_OVERFLOW);
     }
     else
         converted_value = value / MaxFieldType::getScaleMultiplier(scale_from - scale_to);
@@ -274,14 +106,15 @@ convertDecimals(const typename FromDataType::FieldType & value, UInt32 scale_fro
     {
         if (converted_value < std::numeric_limits<typename ToFieldType::NativeType>::min() ||
             converted_value > std::numeric_limits<typename ToFieldType::NativeType>::max())
-            throw Exception("Decimal convert overflow", ErrorCodes::DECIMAL_OVERFLOW);
+            throw Exception(std::string(ToDataType::family_name) + " convert overflow",
+                            ErrorCodes::DECIMAL_OVERFLOW);
     }
 
     return converted_value;
 }
 
 template <typename FromDataType, typename ToDataType>
-inline std::enable_if_t<IsDataTypeDecimal<FromDataType> && IsDataTypeNumber<ToDataType>, typename ToDataType::FieldType>
+inline std::enable_if_t<IsDataTypeDecimal<FromDataType> && IsNumber<typename ToDataType::FieldType>, typename ToDataType::FieldType>
 convertFromDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
 {
     using FromFieldType = typename FromDataType::FieldType;
@@ -299,7 +132,8 @@ convertFromDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
             {
                 if (converted_value < std::numeric_limits<ToFieldType>::min() ||
                     converted_value > std::numeric_limits<ToFieldType>::max())
-                    throw Exception("Decimal convert overflow", ErrorCodes::DECIMAL_OVERFLOW);
+                    throw Exception(std::string(FromDataType::family_name) + " convert overflow",
+                                    ErrorCodes::DECIMAL_OVERFLOW);
             }
             else
             {
@@ -307,7 +141,8 @@ convertFromDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
 
                 if (converted_value < 0 ||
                     converted_value > static_cast<CastIntType>(std::numeric_limits<ToFieldType>::max()))
-                    throw Exception("Decimal convert overflow", ErrorCodes::DECIMAL_OVERFLOW);
+                    throw Exception(std::string(FromDataType::family_name) + " convert overflow",
+                                    ErrorCodes::DECIMAL_OVERFLOW);
             }
         }
         return converted_value;
@@ -315,7 +150,7 @@ convertFromDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
 }
 
 template <typename FromDataType, typename ToDataType>
-inline std::enable_if_t<IsDataTypeNumber<FromDataType> && IsDataTypeDecimal<ToDataType>, typename ToDataType::FieldType>
+inline std::enable_if_t<IsNumber<typename FromDataType::FieldType> && IsDataTypeDecimal<ToDataType>, typename ToDataType::FieldType>
 convertToDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
 {
     using FromFieldType = typename FromDataType::FieldType;
@@ -325,7 +160,8 @@ convertToDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
     if constexpr (std::is_floating_point_v<FromFieldType>)
     {
         if (!std::isfinite(value))
-            throw Exception("Decimal convert overflow. Cannot convert infinity or NaN to decimal", ErrorCodes::DECIMAL_OVERFLOW);
+            throw Exception(std::string(ToDataType::family_name) + " convert overflow. Cannot convert infinity or NaN to decimal",
+                            ErrorCodes::DECIMAL_OVERFLOW);
 
         auto out = value * ToFieldType::getScaleMultiplier(scale);
         if constexpr (std::is_same_v<ToNativeType, Int128>)
@@ -333,12 +169,14 @@ convertToDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
             static constexpr __int128 min_int128 = __int128(0x8000000000000000ll) << 64;
             static constexpr __int128 max_int128 = (__int128(0x7fffffffffffffffll) << 64) + 0xffffffffffffffffll;
             if (out <= static_cast<ToNativeType>(min_int128) || out >= static_cast<ToNativeType>(max_int128))
-                throw Exception("Decimal convert overflow. Float is out of Decimal range", ErrorCodes::DECIMAL_OVERFLOW);
+                throw Exception(std::string(ToDataType::family_name) + " convert overflow. Float is out of Decimal range",
+                                ErrorCodes::DECIMAL_OVERFLOW);
         }
         else
         {
             if (out <= std::numeric_limits<ToNativeType>::min() || out >= std::numeric_limits<ToNativeType>::max())
-                throw Exception("Decimal convert overflow. Float is out of Decimal range", ErrorCodes::DECIMAL_OVERFLOW);
+                throw Exception(std::string(ToDataType::family_name) + " convert overflow. Float is out of Decimal range",
+                                ErrorCodes::DECIMAL_OVERFLOW);
         }
         return out;
     }
@@ -347,6 +185,7 @@ convertToDecimal(const typename FromDataType::FieldType & value, UInt32 scale)
         if constexpr (std::is_same_v<FromFieldType, UInt64>)
             if (value > static_cast<UInt64>(std::numeric_limits<Int64>::max()))
                 return convertDecimals<DataTypeDecimal<Decimal128>, ToDataType>(value, 0, scale);
+
         return convertDecimals<DataTypeDecimal<Decimal64>, ToDataType>(value, 0, scale);
     }
 }

dbms/src/DataTypes/DataTypesNumber.h

@@ -38,16 +38,4 @@ using DataTypeInt64 = DataTypeNumber<Int64>;
 using DataTypeFloat32 = DataTypeNumber<Float32>;
 using DataTypeFloat64 = DataTypeNumber<Float64>;
 
-template <typename DataType> constexpr bool IsDataTypeNumber = false;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<UInt8>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<UInt16>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<UInt32>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<UInt64>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<Int8>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<Int16>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<Int32>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<Int64>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<Float32>> = true;
-template <> inline constexpr bool IsDataTypeNumber<DataTypeNumber<Float64>> = true;
-
 }

dbms/src/DataTypes/IDataType.h

@@ -511,7 +511,8 @@ struct WhichDataType
 
     bool isDate() const { return idx == TypeIndex::Date; }
     bool isDateTime() const { return idx == TypeIndex::DateTime; }
-    bool isDateOrDateTime() const { return isDate() || isDateTime(); }
+    bool isDateTime64() const { return idx == TypeIndex::DateTime64; }
+    bool isDateOrDateTime() const { return isDate() || isDateTime() || isDateTime64(); }
 
     bool isString() const { return idx == TypeIndex::String; }
     bool isFixedString() const { return idx == TypeIndex::FixedString; }
@@ -533,6 +534,7 @@ struct WhichDataType
 
 inline bool isDate(const DataTypePtr & data_type) { return WhichDataType(data_type).isDate(); }
 inline bool isDateOrDateTime(const DataTypePtr & data_type) { return WhichDataType(data_type).isDateOrDateTime(); }
+inline bool isDateTime64(const DataTypePtr & data_type) { return WhichDataType(data_type).isDateTime64(); }
 inline bool isEnum(const DataTypePtr & data_type) { return WhichDataType(data_type).isEnum(); }
 inline bool isDecimal(const DataTypePtr & data_type) { return WhichDataType(data_type).isDecimal(); }
 inline bool isTuple(const DataTypePtr & data_type) { return WhichDataType(data_type).isTuple(); }
@@ -564,6 +566,14 @@ inline bool isFloat(const T & data_type)
     return which.isFloat();
 }
 
+template <typename T>
+inline bool isNativeInteger(const T & data_type)
+{
+    WhichDataType which(data_type);
+    return which.isNativeInt() || which.isNativeUInt();
+}
+
+
 template <typename T>
 inline bool isNativeNumber(const T & data_type)
 {
@@ -585,6 +595,13 @@ inline bool isColumnedAsNumber(const T & data_type)
     return which.isInt() || which.isUInt() || which.isFloat() || which.isDateOrDateTime() || which.isUUID();
 }
 
+template <typename T>
+inline bool isColumnedAsDecimal(const T & data_type)
+{
+    WhichDataType which(data_type);
+    return which.isDecimal() || which.isDateTime64();
+}
+
 template <typename T>
 inline bool isString(const T & data_type)
 {
@@ -615,6 +632,30 @@ inline bool isCompilableType(const DataTypePtr & data_type)
     return data_type->isValueRepresentedByNumber() && !isDecimal(data_type);
 }
 
+template <typename DataType> constexpr bool IsDataTypeDecimal = false;
+template <typename DataType> constexpr bool IsDataTypeNumber = false;
+template <typename DataType> constexpr bool IsDataTypeDateOrDateTime = false;
+
+template <typename DataType> constexpr bool IsDataTypeDecimalOrNumber = IsDataTypeDecimal<DataType> || IsDataTypeNumber<DataType>;
+
+template <typename T>
+class DataTypeDecimal;
+
+template <typename T>
+class DataTypeNumber;
+
+class DataTypeDate;
+class DataTypeDateTime;
+class DataTypeDateTime64;
+
+template <typename T> constexpr bool IsDataTypeDecimal<DataTypeDecimal<T>> = true;
+template <> constexpr bool IsDataTypeDecimal<DataTypeDateTime64> = true;
+
+template <typename T> constexpr bool IsDataTypeNumber<DataTypeNumber<T>> = true;
+
+template <> inline constexpr bool IsDataTypeDateOrDateTime<DataTypeDate> = true;
+template <> inline constexpr bool IsDataTypeDateOrDateTime<DataTypeDateTime> = true;
+template <> inline constexpr bool IsDataTypeDateOrDateTime<DataTypeDateTime64> = true;
 
 }
 

dbms/src/DataTypes/getLeastSupertype.cpp

@@ -12,6 +12,7 @@
 #include <DataTypes/DataTypeNothing.h>
 #include <DataTypes/DataTypeString.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypesNumber.h>
 #include <DataTypes/DataTypesDecimal.h>
 
@@ -212,14 +213,46 @@ DataTypePtr getLeastSupertype(const DataTypes & types)
     {
         UInt32 have_date = type_ids.count(TypeIndex::Date);
         UInt32 have_datetime = type_ids.count(TypeIndex::DateTime);
+        UInt32 have_datetime64 = type_ids.count(TypeIndex::DateTime64);
 
-        if (have_date || have_datetime)
+        if (have_date || have_datetime || have_datetime64)
         {
-            bool all_date_or_datetime = type_ids.size() == (have_date + have_datetime);
+            bool all_date_or_datetime = type_ids.size() == (have_date + have_datetime + have_datetime64);
             if (!all_date_or_datetime)
                 throw Exception(getExceptionMessagePrefix(types) + " because some of them are Date/DateTime and some of them are not", ErrorCodes::NO_COMMON_TYPE);
 
-            return std::make_shared<DataTypeDateTime>();
+            if (have_datetime64 == 0)
+            {
+                return std::make_shared<DataTypeDateTime>();
+            }
+
+            // When DateTime64 involved, make sure that supertype has whole-part precision
+            // big enough to hold max whole-value of any type from `types`.
+            // That would sacrifice scale when comparing DateTime64 of different scales.
+
+            UInt32 max_datetime64_whole_precision = 0;
+            for (const auto & t : types)
+            {
+                if (auto dt64 = typeid_cast<const DataTypeDateTime64 *>(t.get()))
+                {
+                    const auto whole_precision = dt64->getPrecision() - dt64->getScale();
+                    max_datetime64_whole_precision = std::max(whole_precision, max_datetime64_whole_precision);
+                }
+            }
+
+            UInt32 least_decimal_precision = 0;
+            if (have_datetime)
+            {
+                least_decimal_precision = leastDecimalPrecisionFor(TypeIndex::UInt32);
+            }
+            else if (have_date)
+            {
+                least_decimal_precision = leastDecimalPrecisionFor(TypeIndex::UInt16);
+            }
+            max_datetime64_whole_precision = std::max(least_decimal_precision, max_datetime64_whole_precision);
+
+            const UInt32 scale = DataTypeDateTime64::maxPrecision() - max_datetime64_whole_precision;
+            return std::make_shared<DataTypeDateTime64>(scale);
         }
     }
 

dbms/src/DataTypes/tests/gtest_data_type_get_common_type.cpp

@@ -6,117 +6,209 @@
 
 #include <gtest/gtest.h>
 
+namespace DB
+{
+
+bool operator==(const IDataType & left, const IDataType & right)
+{
+    return left.equals(right);
+}
+
+std::ostream & operator<<(std::ostream & ostr, const IDataType & dt)
+{
+    return ostr << dt.getName();
+}
+
+}
 
 using namespace DB;
 
-
-TEST(data_type, data_type_get_common_type_Test)
+auto typeFromString(const std::string & str)
 {
     auto & data_type_factory = DataTypeFactory::instance();
-    auto typeFromString = [& data_type_factory](const std::string & str)
-    {
-        return data_type_factory.get(str);
-    };
+    return data_type_factory.get(str);
+};
 
-    auto typesFromString = [& typeFromString](const std::string & str)
-    {
-        std::istringstream data_types_stream(str);
-        DataTypes data_types;
-        std::string data_type;
-        while (data_types_stream >> data_type)
-            data_types.push_back(typeFromString(data_type));
+auto typesFromString(const std::string & str)
+{
+    std::istringstream data_types_stream(str);
+    DataTypes data_types;
+    std::string data_type;
+    while (data_types_stream >> data_type)
+        data_types.push_back(typeFromString(data_type));
 
-        return data_types;
-    };
+    return data_types;
+};
 
-    ASSERT_TRUE(getLeastSupertype(typesFromString(""))->equals(*typeFromString("Nothing")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Nothing"))->equals(*typeFromString("Nothing")));
+struct TypesTestCase
+{
+    const char * from_types;
+    const char * expected_type = nullptr;
+};
 
-    ASSERT_TRUE(getLeastSupertype(typesFromString("UInt8"))->equals(*typeFromString("UInt8")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("UInt8 UInt8"))->equals(*typeFromString("UInt8")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Int8 Int8"))->equals(*typeFromString("Int8")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("UInt8 Int8"))->equals(*typeFromString("Int16")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("UInt8 Int16"))->equals(*typeFromString("Int16")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("UInt8 UInt32 UInt64"))->equals(*typeFromString("UInt64")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Int8 Int32 Int64"))->equals(*typeFromString("Int64")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("UInt8 UInt32 Int64"))->equals(*typeFromString("Int64")));
+std::ostream & operator<<(std::ostream & ostr, const TypesTestCase & test_case)
+{
+    ostr << "TypesTestCase{\"" << test_case.from_types << "\", ";
+    if (test_case.expected_type)
+        ostr << "\"" << test_case.expected_type << "\"";
+    else
+        ostr << "nullptr";
 
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Float32 Float64"))->equals(*typeFromString("Float64")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Float32 UInt16 Int16"))->equals(*typeFromString("Float32")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Float32 UInt16 Int32"))->equals(*typeFromString("Float64")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Float32 Int16 UInt32"))->equals(*typeFromString("Float64")));
-
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Date Date"))->equals(*typeFromString("Date")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Date DateTime"))->equals(*typeFromString("DateTime")));
-
-    ASSERT_TRUE(getLeastSupertype(typesFromString("String FixedString(32) FixedString(8)"))->equals(*typeFromString("String")));
-
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Array(UInt8) Array(UInt8)"))->equals(*typeFromString("Array(UInt8)")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Array(UInt8) Array(Int8)"))->equals(*typeFromString("Array(Int16)")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Array(Float32) Array(Int16) Array(UInt32)"))->equals(*typeFromString("Array(Float64)")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Array(Array(UInt8)) Array(Array(UInt8))"))->equals(*typeFromString("Array(Array(UInt8))")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Array(Array(UInt8)) Array(Array(Int8))"))->equals(*typeFromString("Array(Array(Int16))")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Array(Date) Array(DateTime)"))->equals(*typeFromString("Array(DateTime)")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Array(String) Array(FixedString(32))"))->equals(*typeFromString("Array(String)")));
-
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Nullable(Nothing) Nothing"))->equals(*typeFromString("Nullable(Nothing)")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Nullable(UInt8) Int8"))->equals(*typeFromString("Nullable(Int16)")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Nullable(Nothing) UInt8 Int8"))->equals(*typeFromString("Nullable(Int16)")));
-
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Tuple(Int8,UInt8) Tuple(UInt8,Int8)"))->equals(*typeFromString("Tuple(Int16,Int16)")));
-    ASSERT_TRUE(getLeastSupertype(typesFromString("Tuple(Nullable(Nothing)) Tuple(Nullable(UInt8))"))->equals(*typeFromString("Tuple(Nullable(UInt8))")));
-
-    EXPECT_ANY_THROW(getLeastSupertype(typesFromString("Int8 String")));
-    EXPECT_ANY_THROW(getLeastSupertype(typesFromString("Int64 UInt64")));
-    EXPECT_ANY_THROW(getLeastSupertype(typesFromString("Float32 UInt64")));
-    EXPECT_ANY_THROW(getLeastSupertype(typesFromString("Float64 Int64")));
-    EXPECT_ANY_THROW(getLeastSupertype(typesFromString("Tuple(Int64) Tuple(UInt64)")));
-    EXPECT_ANY_THROW(getLeastSupertype(typesFromString("Tuple(Int64, Int8) Tuple(UInt64)")));
-    EXPECT_ANY_THROW(getLeastSupertype(typesFromString("Array(Int64) Array(String)")));
-
-
-    ASSERT_TRUE(getMostSubtype(typesFromString(""))->equals(*typeFromString("Nothing")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Nothing"))->equals(*typeFromString("Nothing")));
-
-    ASSERT_TRUE(getMostSubtype(typesFromString("UInt8"))->equals(*typeFromString("UInt8")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("UInt8 UInt8"))->equals(*typeFromString("UInt8")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Int8 Int8"))->equals(*typeFromString("Int8")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("UInt8 Int8"))->equals(*typeFromString("UInt8")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Int8 UInt16"))->equals(*typeFromString("Int8")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("UInt8 UInt32 UInt64"))->equals(*typeFromString("UInt8")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Int8 Int32 Int64"))->equals(*typeFromString("Int8")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("UInt8 Int64 UInt64"))->equals(*typeFromString("UInt8")));
-
-    ASSERT_TRUE(getMostSubtype(typesFromString("Float32 Float64"))->equals(*typeFromString("Float32")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Float32 UInt16 Int16"))->equals(*typeFromString("UInt16")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Float32 UInt16 Int32"))->equals(*typeFromString("UInt16")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Float32 Int16 UInt32"))->equals(*typeFromString("Int16")));
-
-    ASSERT_TRUE(getMostSubtype(typesFromString("DateTime DateTime"))->equals(*typeFromString("DateTime")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Date DateTime"))->equals(*typeFromString("Date")));
-
-    ASSERT_TRUE(getMostSubtype(typesFromString("String FixedString(8)"))->equals(*typeFromString("FixedString(8)")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("FixedString(16) FixedString(8)"))->equals(*typeFromString("Nothing")));
-
-    ASSERT_TRUE(getMostSubtype(typesFromString("Array(UInt8) Array(UInt8)"))->equals(*typeFromString("Array(UInt8)")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Array(UInt8) Array(Int8)"))->equals(*typeFromString("Array(UInt8)")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Array(Float32) Array(Int16) Array(UInt32)"))->equals(*typeFromString("Array(Int16)")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Array(Array(UInt8)) Array(Array(UInt8))"))->equals(*typeFromString("Array(Array(UInt8))")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Array(Array(UInt8)) Array(Array(Int8))"))->equals(*typeFromString("Array(Array(UInt8))")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Array(Date) Array(DateTime)"))->equals(*typeFromString("Array(Date)")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Array(String) Array(FixedString(32))"))->equals(*typeFromString("Array(FixedString(32))")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Array(String) Array(FixedString(32))"))->equals(*typeFromString("Array(FixedString(32))")));
-
-    ASSERT_TRUE(getMostSubtype(typesFromString("Nullable(Nothing) Nothing"))->equals(*typeFromString("Nothing")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Nullable(UInt8) Int8"))->equals(*typeFromString("UInt8")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Nullable(Nothing) UInt8 Int8"))->equals(*typeFromString("Nothing")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Nullable(UInt8) Nullable(Int8)"))->equals(*typeFromString("Nullable(UInt8)")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Nullable(Nothing) Nullable(Int8)"))->equals(*typeFromString("Nullable(Nothing)")));
-
-    ASSERT_TRUE(getMostSubtype(typesFromString("Tuple(Int8,UInt8) Tuple(UInt8,Int8)"))->equals(*typeFromString("Tuple(UInt8,UInt8)")));
-    ASSERT_TRUE(getMostSubtype(typesFromString("Tuple(Nullable(Nothing)) Tuple(Nullable(UInt8))"))->equals(*typeFromString("Tuple(Nullable(Nothing))")));
-
-    EXPECT_ANY_THROW(getMostSubtype(typesFromString("Int8 String"), true));
-    EXPECT_ANY_THROW(getMostSubtype(typesFromString("Nothing"), true));
-    EXPECT_ANY_THROW(getMostSubtype(typesFromString("FixedString(16) FixedString(8) String"), true));
+    return ostr << "}";
 }
+
+class TypeTest : public ::testing::TestWithParam<TypesTestCase>
+{
+public:
+    void SetUp()
+    {
+        const auto & p = GetParam();
+        from_types = typesFromString(p.from_types);
+
+        if (p.expected_type)
+            expected_type = typeFromString(p.expected_type);
+        else
+            expected_type.reset();
+    }
+
+public:
+    DataTypes from_types;
+    DataTypePtr expected_type;
+};
+
+class LeastSuperTypeTest : public TypeTest {};
+
+TEST_P(LeastSuperTypeTest, getLeastSupertype)
+{
+    if (this->expected_type)
+    {
+        ASSERT_EQ(*this->expected_type, *getLeastSupertype(this->from_types));
+    }
+    else
+    {
+        EXPECT_ANY_THROW(getLeastSupertype(this->from_types));
+    }
+}
+
+class MostSubtypeTest : public TypeTest {};
+
+TEST_P(MostSubtypeTest, getLeastSupertype)
+{
+    if (this->expected_type)
+    {
+        ASSERT_EQ(*this->expected_type, *getMostSubtype(this->from_types));
+    }
+    else
+    {
+        EXPECT_ANY_THROW(getMostSubtype(this->from_types, true));
+    }
+}
+
+INSTANTIATE_TEST_CASE_P(data_type,
+    LeastSuperTypeTest,
+    ::testing::ValuesIn(
+        std::initializer_list<TypesTestCase>{
+            {"", "Nothing"},
+            {"Nothing", "Nothing"},
+
+            {"UInt8", "UInt8"},
+            {"UInt8 UInt8", "UInt8"},
+            {"Int8 Int8", "Int8"},
+            {"UInt8 Int8", "Int16"},
+            {"UInt8 Int16", "Int16"},
+            {"UInt8 UInt32 UInt64", "UInt64"},
+            {"Int8 Int32 Int64", "Int64"},
+            {"UInt8 UInt32 Int64", "Int64"},
+
+            {"Float32 Float64", "Float64"},
+            {"Float32 UInt16 Int16", "Float32"},
+            {"Float32 UInt16 Int32", "Float64"},
+            {"Float32 Int16 UInt32", "Float64"},
+
+            {"Date Date", "Date"},
+            {"Date DateTime", "DateTime"},
+            {"Date DateTime64(3)", "DateTime64(3)"},
+            {"DateTime DateTime64(3)", "DateTime64(3)"},
+            {"DateTime DateTime64(0)", "DateTime64(0)"},
+            {"DateTime64(9) DateTime64(3)", "DateTime64(3)"},
+            {"DateTime DateTime64(12)", "DateTime64(8)"},
+            {"Date DateTime64(15)", "DateTime64(13)"},
+
+            {"String FixedString(32) FixedString(8)", "String"},
+
+            {"Array(UInt8) Array(UInt8)", "Array(UInt8)"},
+            {"Array(UInt8) Array(Int8)", "Array(Int16)"},
+            {"Array(Float32) Array(Int16) Array(UInt32)", "Array(Float64)"},
+            {"Array(Array(UInt8)) Array(Array(UInt8))", "Array(Array(UInt8))"},
+            {"Array(Array(UInt8)) Array(Array(Int8))", "Array(Array(Int16))"},
+            {"Array(Date) Array(DateTime)", "Array(DateTime)"},
+            {"Array(String) Array(FixedString(32))", "Array(String)"},
+
+            {"Nullable(Nothing) Nothing", "Nullable(Nothing)"},
+            {"Nullable(UInt8) Int8", "Nullable(Int16)"},
+            {"Nullable(Nothing) UInt8 Int8", "Nullable(Int16)"},
+
+            {"Tuple(Int8,UInt8) Tuple(UInt8,Int8)", "Tuple(Int16,Int16)"},
+            {"Tuple(Nullable(Nothing)) Tuple(Nullable(UInt8))", "Tuple(Nullable(UInt8))"},
+
+            {"Int8 String", nullptr},
+            {"Int64 UInt64", nullptr},
+            {"Float32 UInt64", nullptr},
+            {"Float64 Int64", nullptr},
+            {"Tuple(Int64) Tuple(UInt64)", nullptr},
+            {"Tuple(Int64,Int8) Tuple(UInt64)", nullptr},
+            {"Array(Int64) Array(String)", nullptr},
+        }
+    ),
+);
+
+INSTANTIATE_TEST_CASE_P(data_type,
+    MostSubtypeTest,
+    ::testing::ValuesIn(
+        std::initializer_list<TypesTestCase>{
+            {"", "Nothing"},
+            {"Nothing", "Nothing"},
+
+            {"UInt8", "UInt8"},
+            {"UInt8 UInt8", "UInt8"},
+            {"Int8 Int8", "Int8"},
+            {"UInt8 Int8", "UInt8"},
+            {"Int8 UInt16", "Int8"},
+            {"UInt8 UInt32 UInt64", "UInt8"},
+            {"Int8 Int32 Int64", "Int8"},
+            {"UInt8 Int64 UInt64", "UInt8"},
+
+            {"Float32 Float64", "Float32"},
+            {"Float32 UInt16 Int16", "UInt16"},
+            {"Float32 UInt16 Int32", "UInt16"},
+            {"Float32 Int16 UInt32", "Int16"},
+
+            {"DateTime DateTime", "DateTime"},
+            {"Date DateTime", "Date"},
+
+            {"String FixedString(8)", "FixedString(8)"},
+            {"FixedString(16) FixedString(8)", "Nothing"},
+
+            {"Array(UInt8) Array(UInt8)", "Array(UInt8)"},
+            {"Array(UInt8) Array(Int8)", "Array(UInt8)"},
+            {"Array(Float32) Array(Int16) Array(UInt32)", "Array(Int16)"},
+            {"Array(Array(UInt8)) Array(Array(UInt8))", "Array(Array(UInt8))"},
+            {"Array(Array(UInt8)) Array(Array(Int8))", "Array(Array(UInt8))"},
+            {"Array(Date) Array(DateTime)", "Array(Date)"},
+            {"Array(String) Array(FixedString(32))", "Array(FixedString(32))"},
+            {"Array(String) Array(FixedString(32))", "Array(FixedString(32))"},
+
+            {"Nullable(Nothing) Nothing", "Nothing"},
+            {"Nullable(UInt8) Int8", "UInt8"},
+            {"Nullable(Nothing) UInt8 Int8", "Nothing"},
+            {"Nullable(UInt8) Nullable(Int8)", "Nullable(UInt8)"},
+            {"Nullable(Nothing) Nullable(Int8)", "Nullable(Nothing)"},
+
+            {"Tuple(Int8,UInt8) Tuple(UInt8,Int8)", "Tuple(UInt8,UInt8)"},
+            {"Tuple(Nullable(Nothing)) Tuple(Nullable(UInt8))", "Tuple(Nullable(Nothing))"},
+
+            {"Int8 String", nullptr},
+            {"Nothing", nullptr},
+            {"FixedString(16) FixedString(8) String", nullptr},
+        }),
+);

dbms/src/Formats/ProtobufReader.cpp

@@ -474,6 +474,11 @@ public:
         cannotConvertType("DateTime");
     }
 
+    bool readDateTime64(DateTime64 &, UInt32) override
+    {
+        cannotConvertType("DateTime64");
+    }
+
     bool readDecimal32(Decimal32 &, UInt32, UInt32) override
     {
         cannotConvertType("Decimal32");
@@ -606,6 +611,15 @@ public:
         return true;
     }
 
+    bool readDateTime64(DateTime64 & date_time, UInt32 scale) override
+    {
+        if (!readTempString())
+            return false;
+        ReadBufferFromString buf(temp_string);
+        readDateTime64Text(date_time, scale, buf);
+        return true;
+    }
+
     bool readDecimal32(Decimal32 & decimal, UInt32 precision, UInt32 scale) override { return readDecimal(decimal, precision, scale); }
     bool readDecimal64(Decimal64 & decimal, UInt32 precision, UInt32 scale) override { return readDecimal(decimal, precision, scale); }
     bool readDecimal128(Decimal128 & decimal, UInt32 precision, UInt32 scale) override { return readDecimal(decimal, precision, scale); }
@@ -741,6 +755,11 @@ public:
         return true;
     }
 
+    bool readDateTime64(DateTime64 & date_time, UInt32 scale) override
+    {
+        return readDecimal(date_time, scale);
+    }
+
     bool readDecimal32(Decimal32 & decimal, UInt32, UInt32 scale) override { return readDecimal(decimal, scale); }
     bool readDecimal64(Decimal64 & decimal, UInt32, UInt32 scale) override { return readDecimal(decimal, scale); }
     bool readDecimal128(Decimal128 & decimal, UInt32, UInt32 scale) override { return readDecimal(decimal, scale); }

dbms/src/Formats/ProtobufReader.h

@@ -72,6 +72,7 @@ public:
     bool readUUID(UUID & uuid) { return current_converter->readUUID(uuid); }
     bool readDate(DayNum & date) { return current_converter->readDate(date); }
     bool readDateTime(time_t & tm) { return current_converter->readDateTime(tm); }
+    bool readDateTime64(DateTime64 & tm, UInt32 scale) { return current_converter->readDateTime64(tm, scale); }
 
     bool readDecimal(Decimal32 & decimal, UInt32 precision, UInt32 scale) { return current_converter->readDecimal32(decimal, precision, scale); }
     bool readDecimal(Decimal64 & decimal, UInt32 precision, UInt32 scale) { return current_converter->readDecimal64(decimal, precision, scale); }
@@ -152,6 +153,7 @@ private:
        virtual bool readUUID(UUID &) = 0;
        virtual bool readDate(DayNum &) = 0;
        virtual bool readDateTime(time_t &) = 0;
+       virtual bool readDateTime64(DateTime64 &, UInt32) = 0;
        virtual bool readDecimal32(Decimal32 &, UInt32, UInt32) = 0;
        virtual bool readDecimal64(Decimal64 &, UInt32, UInt32) = 0;
        virtual bool readDecimal128(Decimal128 &, UInt32, UInt32) = 0;
@@ -227,6 +229,7 @@ public:
     bool readUUID(UUID &) { return false; }
     bool readDate(DayNum &) { return false; }
     bool readDateTime(time_t &) { return false; }
+    bool readDateTime64(DateTime64 & /*tm*/, UInt32 /*scale*/) { return false; }
     bool readDecimal(Decimal32 &, UInt32, UInt32) { return false; }
     bool readDecimal(Decimal64 &, UInt32, UInt32) { return false; }
     bool readDecimal(Decimal128 &, UInt32, UInt32) { return false; }

dbms/src/Formats/ProtobufWriter.cpp

@@ -329,6 +329,7 @@ public:
     virtual void writeUUID(const UUID &) override { cannotConvertType("UUID"); }
     virtual void writeDate(DayNum) override { cannotConvertType("Date"); }
     virtual void writeDateTime(time_t) override { cannotConvertType("DateTime"); }
+    virtual void writeDateTime64(DateTime64, UInt32) override { cannotConvertType("DateTime64"); }
     virtual void writeDecimal32(Decimal32, UInt32) override { cannotConvertType("Decimal32"); }
     virtual void writeDecimal64(Decimal64, UInt32) override { cannotConvertType("Decimal64"); }
     virtual void writeDecimal128(const Decimal128 &, UInt32) override { cannotConvertType("Decimal128"); }
@@ -436,6 +437,13 @@ public:
         text_buffer.restart();
     }
 
+    void writeDateTime64(DateTime64 date_time, UInt32 scale) override
+    {
+        writeDateTimeText(date_time, scale, text_buffer);
+        writeField(text_buffer.stringRef());
+        text_buffer.restart();
+    }
+
     void writeDecimal32(Decimal32 decimal, UInt32 scale) override { writeDecimal(decimal, scale); }
     void writeDecimal64(Decimal64 decimal, UInt32 scale) override { writeDecimal(decimal, scale); }
     void writeDecimal128(const Decimal128 & decimal, UInt32 scale) override { writeDecimal(decimal, scale); }
@@ -533,7 +541,7 @@ public:
 
     void writeDate(DayNum date) override { castNumericAndWriteField(static_cast<UInt16>(date)); }
     void writeDateTime(time_t tm) override { castNumericAndWriteField(tm); }
-
+    void writeDateTime64(DateTime64 date_time, UInt32 scale) override { writeDecimal(date_time, scale); }
     void writeDecimal32(Decimal32 decimal, UInt32 scale) override { writeDecimal(decimal, scale); }
     void writeDecimal64(Decimal64 decimal, UInt32 scale) override { writeDecimal(decimal, scale); }
     void writeDecimal128(const Decimal128 & decimal, UInt32 scale) override { writeDecimal(decimal, scale); }

dbms/src/Formats/ProtobufWriter.h

@@ -5,6 +5,9 @@
 #include <common/DayNum.h>
 
 #include "config_formats.h"
+
+#include <memory>
+
 #if USE_PROTOBUF
 
 #include "ProtobufColumnMatcher.h"
@@ -70,6 +73,7 @@ public:
     bool writeUUID(const UUID & uuid) { return writeValueIfPossible(&IConverter::writeUUID, uuid); }
     bool writeDate(DayNum date) { return writeValueIfPossible(&IConverter::writeDate, date); }
     bool writeDateTime(time_t tm) { return writeValueIfPossible(&IConverter::writeDateTime, tm); }
+    bool writeDateTime64(DateTime64 tm, UInt32 scale) { return writeValueIfPossible(&IConverter::writeDateTime64, tm, scale); }
     bool writeDecimal(Decimal32 decimal, UInt32 scale) { return writeValueIfPossible(&IConverter::writeDecimal32, decimal, scale); }
     bool writeDecimal(Decimal64 decimal, UInt32 scale) { return writeValueIfPossible(&IConverter::writeDecimal64, decimal, scale); }
     bool writeDecimal(const Decimal128 & decimal, UInt32 scale) { return writeValueIfPossible(&IConverter::writeDecimal128, decimal, scale); }
@@ -153,6 +157,7 @@ private:
         virtual void writeUUID(const UUID &) = 0;
         virtual void writeDate(DayNum) = 0;
         virtual void writeDateTime(time_t) = 0;
+        virtual void writeDateTime64(DateTime64, UInt32 scale) = 0;
         virtual void writeDecimal32(Decimal32, UInt32) = 0;
         virtual void writeDecimal64(Decimal64, UInt32) = 0;
         virtual void writeDecimal128(const Decimal128 &, UInt32) = 0;
@@ -257,6 +262,7 @@ public:
     bool writeUUID(const UUID & /* value */) { return false; }
     bool writeDate(DayNum /* date */) { return false; }
     bool writeDateTime(time_t /* tm */) { return false; }
+    bool writeDateTime64(DateTime64 /*tm*/, UInt32 /*scale*/) { return false; }
     bool writeDecimal(Decimal32 /* decimal */, UInt32 /* scale */) { return false; }
     bool writeDecimal(Decimal64 /* decimal */, UInt32 /* scale */) { return false; }
     bool writeDecimal(const Decimal128 & /* decimal */, UInt32 /* scale */) { return false; }

dbms/src/Functions/CustomWeekTransforms.h

@@ -3,6 +3,7 @@
 #include <Columns/ColumnVector.h>
 #include <Columns/ColumnsNumber.h>
 #include <Core/Types.h>
+#include <Core/DecimalFunctions.h>
 #include <Functions/FunctionHelpers.h>
 #include <Functions/extractTimeZoneFromFunctionArguments.h>
 #include <Common/Exception.h>
@@ -90,24 +91,33 @@ struct ToStartOfWeekImpl
 template <typename FromType, typename ToType, typename Transform>
 struct Transformer
 {
-    static void
-    vector(const PaddedPODArray<FromType> & vec_from, PaddedPODArray<ToType> & vec_to, UInt8 week_mode, const DateLUTImpl & time_zone)
+    Transformer(Transform transform_)
+        : transform(std::move(transform_))
+    {}
+
+    template <typename FromVectorType, typename ToVectorType>
+    void
+    vector(const FromVectorType & vec_from, ToVectorType & vec_to, UInt8 week_mode, const DateLUTImpl & time_zone) const
     {
         size_t size = vec_from.size();
         vec_to.resize(size);
 
         for (size_t i = 0; i < size; ++i)
-            vec_to[i] = Transform::execute(vec_from[i], week_mode, time_zone);
+            vec_to[i] = transform.execute(vec_from[i], week_mode, time_zone);
     }
+
+private:
+    const Transform transform;
 };
 
 
-template <typename FromType, typename ToType, typename Transform>
+template <typename FromDataType, typename ToDataType>
 struct CustomWeekTransformImpl
 {
-    static void execute(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/)
+    template <typename Transform>
+    static void execute(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/, Transform transform = {})
     {
-        using Op = Transformer<FromType, ToType, Transform>;
+        const auto op = Transformer<typename FromDataType::FieldType, typename ToDataType::FieldType, Transform>{std::move(transform)};
 
         UInt8 week_mode = DEFAULT_WEEK_MODE;
         if (arguments.size() > 1)
@@ -118,10 +128,10 @@ struct CustomWeekTransformImpl
 
         const DateLUTImpl & time_zone = extractTimeZoneFromFunctionArguments(block, arguments, 2, 0);
         const ColumnPtr source_col = block.getByPosition(arguments[0]).column;
-        if (const auto * sources = checkAndGetColumn<ColumnVector<FromType>>(source_col.get()))
+        if (const auto * sources = checkAndGetColumn<typename FromDataType::ColumnType>(source_col.get()))
         {
-            auto col_to = ColumnVector<ToType>::create();
-            Op::vector(sources->getData(), col_to->getData(), week_mode, time_zone);
+            auto col_to = ToDataType::ColumnType::create();
+            op.vector(sources->getData(), col_to->getData(), week_mode, time_zone);
             block.getByPosition(result).column = std::move(col_to);
         }
         else

dbms/src/Functions/DateTimeTransforms.h

@@ -1,11 +1,14 @@
 #pragma once
 #include <Core/Types.h>
+#include <Core/DecimalFunctions.h>
 #include <Common/Exception.h>
 #include <common/DateLUTImpl.h>
 #include <Columns/ColumnVector.h>
+#include <Columns/ColumnDecimal.h>
 #include <Functions/FunctionHelpers.h>
 #include <Functions/extractTimeZoneFromFunctionArguments.h>
-
+#include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 
 namespace DB
 {
@@ -629,32 +632,36 @@ struct ToYYYYMMDDhhmmssImpl
 template <typename FromType, typename ToType, typename Transform>
 struct Transformer
 {
-    static void vector(const PaddedPODArray<FromType> & vec_from, PaddedPODArray<ToType> & vec_to, const DateLUTImpl & time_zone)
+    template <typename FromTypeVector, typename ToTypeVector>
+    static void vector(const FromTypeVector & vec_from, ToTypeVector & vec_to, const DateLUTImpl & time_zone, const Transform & transform)
     {
         size_t size = vec_from.size();
         vec_to.resize(size);
 
         for (size_t i = 0; i < size; ++i)
-            vec_to[i] = Transform::execute(vec_from[i], time_zone);
+            vec_to[i] = transform.execute(vec_from[i], time_zone);
     }
 };
 
 
-template <typename FromType, typename ToType, typename Transform>
+template <typename FromDataType, typename ToDataType, typename Transform>
 struct DateTimeTransformImpl
 {
-    static void execute(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/)
+    static void execute(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/, const Transform & transform = {})
     {
-        using Op = Transformer<FromType, ToType, Transform>;
+        using Op = Transformer<typename FromDataType::FieldType, typename ToDataType::FieldType, Transform>;
 
         const DateLUTImpl & time_zone = extractTimeZoneFromFunctionArguments(block, arguments, 1, 0);
 
         const ColumnPtr source_col = block.getByPosition(arguments[0]).column;
-        if (const auto * sources = checkAndGetColumn<ColumnVector<FromType>>(source_col.get()))
+        if (const auto * sources = checkAndGetColumn<typename FromDataType::ColumnType>(source_col.get()))
         {
-            auto col_to = ColumnVector<ToType>::create();
-            Op::vector(sources->getData(), col_to->getData(), time_zone);
-            block.getByPosition(result).column = std::move(col_to);
+            auto mutable_result_col = block.getByPosition(result).type->createColumn();
+            auto * col_to = assert_cast<typename ToDataType::ColumnType *>(mutable_result_col.get());
+
+            Op::vector(sources->getData(), col_to->getData(), time_zone, transform);
+
+            block.getByPosition(result).column = std::move(mutable_result_col);
         }
         else
         {

dbms/src/Functions/FunctionBinaryArithmetic.h

@@ -9,6 +9,7 @@
 #include <DataTypes/DataTypesDecimal.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypeInterval.h>
 #include <DataTypes/DataTypeAggregateFunction.h>
 #include <DataTypes/Native.h>

dbms/src/Functions/FunctionCustomWeekToSomething.h

@@ -1,5 +1,6 @@
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <Functions/CustomWeekTransforms.h>
 #include <Functions/IFunction.h>
 #include <Functions/extractTimeZoneFromFunctionArguments.h>
@@ -100,11 +101,17 @@ public:
         WhichDataType which(from_type);
 
         if (which.isDate())
-            CustomWeekTransformImpl<DataTypeDate::FieldType, typename ToDataType::FieldType, Transform>::execute(
-                block, arguments, result, input_rows_count);
+            CustomWeekTransformImpl<DataTypeDate, ToDataType>::execute(
+                block, arguments, result, input_rows_count, Transform{});
         else if (which.isDateTime())
-            CustomWeekTransformImpl<DataTypeDateTime::FieldType, typename ToDataType::FieldType, Transform>::execute(
-                block, arguments, result, input_rows_count);
+            CustomWeekTransformImpl<DataTypeDateTime, ToDataType>::execute(
+                block, arguments, result, input_rows_count, Transform{});
+        else if (which.isDateTime64())
+        {
+            CustomWeekTransformImpl<DataTypeDateTime64, ToDataType>::execute(
+                block, arguments, result, input_rows_count,
+                DateTime64BasicTransformWrapper<Transform>{assert_cast<const DataTypeDateTime64 *>(from_type)->getScale()});
+        }
         else
             throw Exception(
                 "Illegal type " + block.getByPosition(arguments[0]).type->getName() + " of argument of function " + getName(),

dbms/src/Functions/FunctionDateOrDateTimeAddInterval.h

@@ -2,6 +2,7 @@
 
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 
 #include <Columns/ColumnVector.h>
 
@@ -22,9 +23,47 @@ namespace ErrorCodes
     extern const int ILLEGAL_COLUMN;
 }
 
-
-struct AddSecondsImpl
+/// AddOnDateTime64DefaultImpl provides default implementation of add-X functionality for DateTime64.
+///
+/// Default implementation is not to change fractional part, but only modify whole part as if it was DateTime.
+/// That means large whole values (for scale less than 9) might not fit into UInt32-range,
+/// and hence default implementation will produce incorrect results.
+template <typename T>
+struct AddOnDateTime64DefaultImpl
 {
+    /*explicit*/ AddOnDateTime64DefaultImpl(UInt32 scale_ = 0)
+        : scale_multiplier(DecimalUtils::scaleMultiplier<DateTime64::NativeType>(scale_))
+    {}
+
+    // Default implementation for add/sub on DateTime64: do math on whole part (the same way as for DateTime), leave fractional as it is.
+    inline DateTime64 execute(const DateTime64 & t, Int64 delta, const DateLUTImpl & time_zone) const
+    {
+        const auto components = DecimalUtils::splitWithScaleMultiplier(t, scale_multiplier);
+
+        const auto whole = static_cast<const T*>(this)->execute(static_cast<UInt32>(components.whole), delta, time_zone);
+        return DecimalUtils::decimalFromComponentsWithMultiplier<DateTime64>(static_cast<DateTime64::NativeType>(whole), components.fractional, scale_multiplier);
+    }
+
+    UInt32 scale_multiplier = 1;
+};
+
+
+/// Type of first argument of 'execute' function overload defines what INPUT DataType it is used for.
+/// Return type defines what is the OUTPUT (return) type of the CH function.
+/// Corresponding types:
+///  - UInt16     => DataTypeDate
+///  - UInt32     => DataTypeDateTime
+///  - DateTime64 => DataTypeDateTime64
+/// Please note that INPUT and OUTPUT types may differ, e.g.:
+///  - 'AddSecondsImpl::execute(UInt32, ...) -> UInt32' is available to the ClickHouse users as 'addSeconds(DateTime, ...) -> DateTime'
+///  - 'AddSecondsImpl::execute(UInt16, ...) -> UInt32' is available to the ClickHouse users as 'addSeconds(Date, ...) -> DateTime'
+
+struct AddSecondsImpl : public AddOnDateTime64DefaultImpl<AddSecondsImpl>
+{
+    using Base = AddOnDateTime64DefaultImpl<AddSecondsImpl>;
+    using Base::Base;
+    using Base::execute;
+
     static constexpr auto name = "addSeconds";
 
     static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl &)
@@ -38,8 +77,12 @@ struct AddSecondsImpl
     }
 };
 
-struct AddMinutesImpl
+struct AddMinutesImpl : public AddOnDateTime64DefaultImpl<AddMinutesImpl>
 {
+    using Base = AddOnDateTime64DefaultImpl<AddMinutesImpl>;
+    using Base::Base;
+    using Base::execute;
+
     static constexpr auto name = "addMinutes";
 
     static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl &)
@@ -53,8 +96,12 @@ struct AddMinutesImpl
     }
 };
 
-struct AddHoursImpl
+struct AddHoursImpl : public AddOnDateTime64DefaultImpl<AddHoursImpl>
 {
+    using Base = AddOnDateTime64DefaultImpl<AddHoursImpl>;
+    using Base::Base;
+    using Base::execute;
+
     static constexpr auto name = "addHours";
 
     static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl &)
@@ -68,10 +115,20 @@ struct AddHoursImpl
     }
 };
 
-struct AddDaysImpl
+struct AddDaysImpl : public AddOnDateTime64DefaultImpl<AddDaysImpl>
 {
+    using Base = AddOnDateTime64DefaultImpl<AddDaysImpl>;
+    using Base::Base;
+    using Base::execute;
+
     static constexpr auto name = "addDays";
 
+//    static inline UInt32 execute(UInt64 t, Int64 delta, const DateLUTImpl & time_zone)
+//    {
+//        // TODO (nemkov): LUT does not support out-of range date values for now.
+//        return time_zone.addDays(t, delta);
+//    }
+
     static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
     {
         return time_zone.addDays(t, delta);
@@ -83,8 +140,12 @@ struct AddDaysImpl
     }
 };
 
-struct AddWeeksImpl
+struct AddWeeksImpl : public AddOnDateTime64DefaultImpl<AddWeeksImpl>
 {
+    using Base = AddOnDateTime64DefaultImpl<AddWeeksImpl>;
+    using Base::Base;
+    using Base::execute;
+
     static constexpr auto name = "addWeeks";
 
     static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
@@ -98,8 +159,12 @@ struct AddWeeksImpl
     }
 };
 
-struct AddMonthsImpl
+struct AddMonthsImpl : public AddOnDateTime64DefaultImpl<AddMonthsImpl>
 {
+    using Base = AddOnDateTime64DefaultImpl<AddMonthsImpl>;
+    using Base::Base;
+    using Base::execute;
+
     static constexpr auto name = "addMonths";
 
     static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
@@ -113,8 +178,12 @@ struct AddMonthsImpl
     }
 };
 
-struct AddQuartersImpl
+struct AddQuartersImpl : public AddOnDateTime64DefaultImpl<AddQuartersImpl>
 {
+    using Base = AddOnDateTime64DefaultImpl<AddQuartersImpl>;
+    using Base::Base;
+    using Base::execute;
+
     static constexpr auto name = "addQuarters";
 
     static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
@@ -128,8 +197,12 @@ struct AddQuartersImpl
     }
 };
 
-struct AddYearsImpl
+struct AddYearsImpl : public AddOnDateTime64DefaultImpl<AddYearsImpl>
 {
+    using Base = AddOnDateTime64DefaultImpl<AddYearsImpl>;
+    using Base::Base;
+    using Base::execute;
+
     static constexpr auto name = "addYears";
 
     static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
@@ -143,19 +216,16 @@ struct AddYearsImpl
     }
 };
 
-
 template <typename Transform>
-struct SubtractIntervalImpl
+struct SubtractIntervalImpl : public Transform
 {
-    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
+    using Transform::Transform;
+
+    template <typename T>
+    inline auto execute(T t, Int64 delta, const DateLUTImpl & time_zone) const
     {
         return Transform::execute(t, -delta, time_zone);
     }
-
-    static inline UInt16 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
-    {
-        return Transform::execute(d, -delta, time_zone);
-    }
 };
 
 struct SubtractSecondsImpl : SubtractIntervalImpl<AddSecondsImpl> { static constexpr auto name = "subtractSeconds"; };
@@ -168,68 +238,77 @@ struct SubtractQuartersImpl : SubtractIntervalImpl<AddQuartersImpl> { static con
 struct SubtractYearsImpl : SubtractIntervalImpl<AddYearsImpl> { static constexpr auto name = "subtractYears"; };
 
 
-template <typename FromType, typename ToType, typename Transform>
+template <typename Transform>
 struct Adder
 {
-    static void vector_vector(const PaddedPODArray<FromType> & vec_from, PaddedPODArray<ToType> & vec_to, const IColumn & delta, const DateLUTImpl & time_zone)
+    const Transform transform;
+
+    explicit Adder(Transform transform_)
+        : transform(std::move(transform_))
+    {}
+
+    template <typename FromVectorType, typename ToVectorType>
+    void vector_vector(const FromVectorType & vec_from, ToVectorType & vec_to, const IColumn & delta, const DateLUTImpl & time_zone) const
     {
         size_t size = vec_from.size();
         vec_to.resize(size);
 
         for (size_t i = 0; i < size; ++i)
-            vec_to[i] = Transform::execute(vec_from[i], delta.getInt(i), time_zone);
+            vec_to[i] = transform.execute(vec_from[i], delta.getInt(i), time_zone);
     }
 
-    static void vector_constant(const PaddedPODArray<FromType> & vec_from, PaddedPODArray<ToType> & vec_to, Int64 delta, const DateLUTImpl & time_zone)
+    template <typename FromVectorType, typename ToVectorType>
+    void vector_constant(const FromVectorType & vec_from, ToVectorType & vec_to, Int64 delta, const DateLUTImpl & time_zone) const
     {
         size_t size = vec_from.size();
         vec_to.resize(size);
 
         for (size_t i = 0; i < size; ++i)
-            vec_to[i] = Transform::execute(vec_from[i], delta, time_zone);
+            vec_to[i] = transform.execute(vec_from[i], delta, time_zone);
     }
 
-    static void constant_vector(const FromType & from, PaddedPODArray<ToType> & vec_to, const IColumn & delta, const DateLUTImpl & time_zone)
+    template <typename FromType, typename ToVectorType>
+    void constant_vector(const FromType & from, ToVectorType & vec_to, const IColumn & delta, const DateLUTImpl & time_zone) const
     {
         size_t size = delta.size();
         vec_to.resize(size);
 
         for (size_t i = 0; i < size; ++i)
-            vec_to[i] = Transform::execute(from, delta.getInt(i), time_zone);
+            vec_to[i] = transform.execute(from, delta.getInt(i), time_zone);
     }
 };
 
 
-template <typename FromType, typename Transform>
+template <typename FromDataType, typename ToDataType, typename Transform>
 struct DateTimeAddIntervalImpl
 {
-    static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
+    static void execute(Transform transform, Block & block, const ColumnNumbers & arguments, size_t result)
     {
-        using ToType = decltype(Transform::execute(FromType(), 0, std::declval<DateLUTImpl>()));
-        using Op = Adder<FromType, ToType, Transform>;
+        using FromValueType = typename FromDataType::FieldType;
+        using FromColumnType = typename FromDataType::ColumnType;
+        using ToColumnType = typename ToDataType::ColumnType;
+
+        auto op = Adder<Transform>{std::move(transform)};
 
         const DateLUTImpl & time_zone = extractTimeZoneFromFunctionArguments(block, arguments, 2, 0);
 
         const ColumnPtr source_col = block.getByPosition(arguments[0]).column;
 
-        if (const auto * sources = checkAndGetColumn<ColumnVector<FromType>>(source_col.get()))
-        {
-            auto col_to = ColumnVector<ToType>::create();
+        auto result_col = block.getByPosition(result).type->createColumn();
+        auto col_to = assert_cast<ToColumnType *>(result_col.get());
 
+        if (const auto * sources = checkAndGetColumn<FromColumnType>(source_col.get()))
+        {
             const IColumn & delta_column = *block.getByPosition(arguments[1]).column;
 
             if (const auto * delta_const_column = typeid_cast<const ColumnConst *>(&delta_column))
-                Op::vector_constant(sources->getData(), col_to->getData(), delta_const_column->getField().get<Int64>(), time_zone);
+                op.vector_constant(sources->getData(), col_to->getData(), delta_const_column->getField().get<Int64>(), time_zone);
             else
-                Op::vector_vector(sources->getData(), col_to->getData(), delta_column, time_zone);
-
-            block.getByPosition(result).column = std::move(col_to);
+                op.vector_vector(sources->getData(), col_to->getData(), delta_column, time_zone);
         }
-        else if (const auto * sources_const = checkAndGetColumnConst<ColumnVector<FromType>>(source_col.get()))
+        else if (const auto * sources_const = checkAndGetColumnConst<FromColumnType>(source_col.get()))
         {
-            auto col_to = ColumnVector<ToType>::create();
-            Op::constant_vector(sources_const->template getValue<FromType>(), col_to->getData(), *block.getByPosition(arguments[1]).column, time_zone);
-            block.getByPosition(result).column = std::move(col_to);
+            op.constant_vector(sources_const->template getValue<FromValueType>(), col_to->getData(), *block.getByPosition(arguments[1]).column, time_zone);
         }
         else
         {
@@ -237,9 +316,21 @@ struct DateTimeAddIntervalImpl
                 + " of first argument of function " + Transform::name,
                 ErrorCodes::ILLEGAL_COLUMN);
         }
+
+        block.getByPosition(result).column = std::move(result_col);
     }
 };
 
+namespace date_and_time_type_details
+{
+// Compile-time mapping of value (DataType::FieldType) types to corresponding DataType
+template <typename FieldType> struct ResultDataTypeMap {};
+template <> struct ResultDataTypeMap<UInt16>     { using ResultDataType = DataTypeDate; };
+template <> struct ResultDataTypeMap<Int16>      { using ResultDataType = DataTypeDate; };
+template <> struct ResultDataTypeMap<UInt32>     { using ResultDataType = DataTypeDateTime; };
+template <> struct ResultDataTypeMap<Int32>      { using ResultDataType = DataTypeDateTime; };
+template <> struct ResultDataTypeMap<DateTime64> { using ResultDataType = DataTypeDateTime64; };
+}
 
 template <typename Transform>
 class FunctionDateOrDateTimeAddInterval : public IFunction
@@ -286,20 +377,58 @@ public:
                     ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
         }
 
-        if (WhichDataType(arguments[0].type).isDate())
+        switch (arguments[0].type->getTypeId())
         {
-            if (std::is_same_v<decltype(Transform::execute(DataTypeDate::FieldType(), 0, std::declval<DateLUTImpl>())), UInt16>)
-                return std::make_shared<DataTypeDate>();
-            else
-                return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, 2, 0));
+            case TypeIndex::Date:
+                return resolveReturnType<DataTypeDate>(arguments);
+            case TypeIndex::DateTime:
+                return resolveReturnType<DataTypeDateTime>(arguments);
+            case TypeIndex::DateTime64:
+                return resolveReturnType<DataTypeDateTime64>(arguments);
+            default:
+            {
+                throw Exception("Invalid type of 1st argument of function " + getName() + ": "
+                    + arguments[0].type->getName() + ", expected: Date, DateTime or DateTime64.",
+                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
+            }
+        }
+    }
+
+    // Helper templates to deduce return type based on argument type, since some overloads may promote or denote types, e.g. addSeconds(Date, 1) => DateTime
+    template <typename FieldType>
+    using TransformExecuteReturnType = decltype(std::declval<Transform>().execute(FieldType(), 0, std::declval<DateLUTImpl>()));
+
+    // Deduces RETURN DataType from INTPUT DataType, based on return type of Transform{}.execute(INPUT_TYPE, UInt64, DateLUTImpl).
+    // e.g. for Transform-type that has execute()-overload with 'UInt16' input and 'UInt32' return,
+    // argument type is expected to be 'Date', and result type is deduced to be 'DateTime'.
+    template <typename FromDataType>
+    using TransformResultDataType = typename date_and_time_type_details::ResultDataTypeMap<TransformExecuteReturnType<typename FromDataType::FieldType>>::ResultDataType;
+
+    template <typename FromDataType>
+    DataTypePtr resolveReturnType(const ColumnsWithTypeAndName & arguments) const
+    {
+        using ResultDataType = TransformResultDataType<FromDataType>;
+
+        if constexpr (std::is_same_v<ResultDataType, DataTypeDate>)
+            return std::make_shared<DataTypeDate>();
+        else if constexpr (std::is_same_v<ResultDataType, DataTypeDateTime>)
+        {
+            return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, 2, 0));
+        }
+        else if constexpr (std::is_same_v<ResultDataType, DataTypeDateTime64>)
+        {
+            // TODO (vnemkov): what if there is an overload of Transform::execute() that returns DateTime64 from DateTime or Date ?
+            // Shall we use the default scale or one from optional argument ?
+            const auto & datetime64_type = assert_cast<const DataTypeDateTime64 &>(*arguments[0].type);
+            return std::make_shared<DataTypeDateTime64>(datetime64_type.getScale(), extractTimeZoneNameFromFunctionArguments(arguments, 2, 0));
         }
         else
         {
-            if (std::is_same_v<decltype(Transform::execute(DataTypeDateTime::FieldType(), 0, std::declval<DateLUTImpl>())), UInt16>)
-                return std::make_shared<DataTypeDate>();
-            else
-                return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, 2, 0));
+            static_assert("Failed to resolve return type.");
         }
+
+        //to make PVS and GCC happy.
+        return nullptr;
     }
 
     bool useDefaultImplementationForConstants() const override { return true; }
@@ -311,9 +440,17 @@ public:
         WhichDataType which(from_type);
 
         if (which.isDate())
-            DateTimeAddIntervalImpl<DataTypeDate::FieldType, Transform>::execute(block, arguments, result);
+        {
+            DateTimeAddIntervalImpl<DataTypeDate, TransformResultDataType<DataTypeDate>, Transform>::execute(Transform{}, block, arguments, result);
+        }
         else if (which.isDateTime())
-            DateTimeAddIntervalImpl<DataTypeDateTime::FieldType, Transform>::execute(block, arguments, result);
+        {
+            DateTimeAddIntervalImpl<DataTypeDateTime, TransformResultDataType<DataTypeDateTime>, Transform>::execute(Transform{}, block, arguments, result);
+        }
+        else if (const auto * datetime64_type = assert_cast<const DataTypeDateTime64 *>(from_type))
+        {
+            DateTimeAddIntervalImpl<DataTypeDateTime64, TransformResultDataType<DataTypeDateTime64>, Transform>::execute(Transform{datetime64_type->getScale()}, block, arguments, result);
+        }
         else
             throw Exception("Illegal type " + block.getByPosition(arguments[0]).type->getName() + " of argument of function " + getName(),
                 ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

dbms/src/Functions/FunctionDateOrDateTimeToSomething.h

@@ -1,5 +1,6 @@
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <Functions/IFunction.h>
 #include <Functions/extractTimeZoneFromFunctionArguments.h>
 #include <Functions/DateTimeTransforms.h>
@@ -15,6 +16,25 @@ namespace ErrorCodes
     extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
 }
 
+template<class Transform>
+struct WithDateTime64Converter : public Transform
+{
+    UInt8 scale;
+    Transform transform;
+
+    explicit WithDateTime64Converter(UInt8 scale_, Transform transform_ = {})
+        : scale(scale_),
+          transform(std::move(transform_))
+    {}
+
+    inline auto execute(DataTypeDateTime64::FieldType t, const DateLUTImpl & time_zone) const
+    {
+        auto x = DateTime64(t);
+        auto res = transform.execute(static_cast<UInt32>(DecimalUtils::getWholePart(x, scale)), time_zone);
+        return res;
+    }
+};
+
 
 /// See DateTimeTransforms.h
 template <typename ToDataType, typename Transform>
@@ -67,8 +87,10 @@ public:
                 ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
 
         /// For DateTime, if time zone is specified, attach it to type.
-        if (std::is_same_v<ToDataType, DataTypeDateTime>)
-            return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, 1, 0));
+        if constexpr (std::is_same_v<ToDataType, DataTypeDateTime>)
+            return std::make_shared<ToDataType>(extractTimeZoneNameFromFunctionArguments(arguments, 1, 0));
+        if constexpr (std::is_same_v<ToDataType, DataTypeDateTime64>)
+            return std::make_shared<ToDataType>(extractTimeZoneNameFromFunctionArguments(arguments, 1, 0));
         else
             return std::make_shared<ToDataType>();
     }
@@ -82,9 +104,16 @@ public:
         WhichDataType which(from_type);
 
         if (which.isDate())
-            DateTimeTransformImpl<DataTypeDate::FieldType, typename ToDataType::FieldType, Transform>::execute(block, arguments, result, input_rows_count);
+            DateTimeTransformImpl<DataTypeDate, ToDataType, Transform>::execute(block, arguments, result, input_rows_count);
         else if (which.isDateTime())
-            DateTimeTransformImpl<DataTypeDateTime::FieldType, typename ToDataType::FieldType, Transform>::execute(block, arguments, result, input_rows_count);
+            DateTimeTransformImpl<DataTypeDateTime, ToDataType, Transform>::execute(block, arguments, result, input_rows_count);
+        else if (which.isDateTime64())
+        {
+            const auto scale = static_cast<const DataTypeDateTime64 *>(from_type)->getScale();
+            WithDateTime64Converter<Transform> transformer(scale);
+
+            DateTimeTransformImpl<DataTypeDateTime64, ToDataType, WithDateTime64Converter<Transform>>::execute(block, arguments, result, input_rows_count, transformer);
+        }
         else
             throw Exception("Illegal type " + block.getByPosition(arguments[0]).type->getName() + " of argument of function " + getName(),
                 ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

dbms/src/Functions/FunctionHelpers.cpp

@@ -103,8 +103,8 @@ Block createBlockWithNestedColumns(const Block & block, const ColumnNumbers & ar
 }
 
 void validateArgumentType(const IFunction & func, const DataTypes & arguments,
-                                 size_t argument_index, bool (* validator_func)(const IDataType &),
-                                 const char * expected_type_description)
+                          size_t argument_index, bool (* validator_func)(const IDataType &),
+                          const char * expected_type_description)
 {
     if (arguments.size() <= argument_index)
         throw Exception("Incorrect number of arguments of function " + func.getName(),
@@ -119,6 +119,75 @@ void validateArgumentType(const IFunction & func, const DataTypes & arguments,
                         ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 }
 
+namespace
+{
+void validateArgumentsImpl(const IFunction & func,
+                           const ColumnsWithTypeAndName & arguments,
+                           size_t argument_offset,
+                           const FunctionArgumentTypeValidators & validators)
+{
+    for (size_t i = 0; i < validators.size(); ++i)
+    {
+        const auto argument_index = i + argument_offset;
+        if (argument_index >= arguments.size())
+        {
+            break;
+        }
+
+        const auto & arg = arguments[i + argument_offset];
+        const auto validator = validators[i];
+        if (!validator.validator_func(*arg.type))
+            throw Exception("Illegal type " + arg.type->getName() +
+                            " of " + std::to_string(i) +
+                            " argument of function " + func.getName() +
+                            " expected " + validator.expected_type_description,
+                            ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
+    }
+}
+
+}
+
+void validateFunctionArgumentTypes(const IFunction & func,
+                                   const ColumnsWithTypeAndName & arguments,
+                                   const FunctionArgumentTypeValidators & mandatory_args,
+                                   const FunctionArgumentTypeValidators & optional_args)
+{
+    if (arguments.size() < mandatory_args.size())
+    {
+        auto joinArgumentTypes = [](const auto & args, const String sep = ", ") -> String
+        {
+            String result;
+            for (const auto & a : args)
+            {
+                using A = std::decay_t<decltype(a)>;
+                if constexpr (std::is_same_v<A, FunctionArgumentTypeValidator>)
+                    result += a.expected_type_description;
+                else if constexpr (std::is_same_v<A, ColumnWithTypeAndName>)
+                    result += a.type->getName();
+
+                result += sep;
+            }
+
+            if (args.size() != 0)
+                result.erase(result.end() - sep.length(), result.end());
+
+            return result;
+        };
+
+        throw Exception("Incorrect number of arguments of function " + func.getName()
+                        + " provided " + std::to_string(arguments.size()) + " (" + joinArgumentTypes(arguments) + ")"
+                        + " expected " + std::to_string(mandatory_args.size()) + (optional_args.size() ? " or " + std::to_string(mandatory_args.size() + optional_args.size()) : "")
+                        + " (" + joinArgumentTypes(mandatory_args) + (optional_args.size() ? ", [" + joinArgumentTypes(mandatory_args) + "]" : "") + ")",
+                        ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
+    }
+
+    validateArgumentsImpl(func, arguments, 0, mandatory_args);
+    if (optional_args.size())
+    {
+        validateArgumentsImpl(func, arguments, mandatory_args.size(), optional_args);
+    }
+}
+
 std::pair<std::vector<const IColumn *>, const ColumnArray::Offset *>
 checkAndGetNestedArrayOffset(const IColumn ** columns, size_t num_arguments)
 {

dbms/src/Functions/FunctionHelpers.h

@@ -90,6 +90,35 @@ void validateArgumentType(const IFunction & func, const DataTypes & arguments,
         size_t argument_index, bool (* validator_func)(const IDataType &),
         const char * expected_type_description);
 
+// Simple validator that is used in conjunction with validateFunctionArgumentTypes() to check if function arguments are as expected.
+struct FunctionArgumentTypeValidator
+{
+    bool (* validator_func)(const IDataType &);
+    const char * expected_type_description;
+};
+
+using FunctionArgumentTypeValidators = std::vector<FunctionArgumentTypeValidator>;
+
+/** Validate that function arguments match specification.
+ *
+ * Designed to simplify argument validation
+ * for functions with variable arguments (e.g. depending on result type or other trait).
+ * first, checks that mandatory args present and have valid type.
+ * second, checks optional arguents types, skipping ones that are missing.
+ *
+ * Please note that if you have several optional arguments, like f([a, b, c]),
+ * only these calls are considered valid:
+ *  f(a)
+ *  f(a, b)
+ *  f(a, b, c)
+ *
+ * But NOT these: f(a, c), f(b, c)
+ * In other words you can't skip
+ *
+ * If any mandatory arg is missing, throw an exception, with explicit description of expected arguments.
+ */
+void validateFunctionArgumentTypes(const IFunction & func, const ColumnsWithTypeAndName & arguments, const FunctionArgumentTypeValidators & mandatory_args, const FunctionArgumentTypeValidators & optional_args = {});
+
 /// Checks if a list of array columns have equal offsets. Return a pair of nested columns and offsets if true, otherwise throw.
 std::pair<std::vector<const IColumn *>, const ColumnArray::Offset *>
 checkAndGetNestedArrayOffset(const IColumn ** columns, size_t num_arguments);

dbms/src/Functions/FunctionsComparison.h

@@ -13,6 +13,7 @@
 
 #include <DataTypes/DataTypesNumber.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeString.h>
 #include <DataTypes/DataTypeUUID.h>
@@ -684,7 +685,7 @@ private:
             return true;
         };
 
-        if (!callOnBasicTypes<true, false, true, false>(left_number, right_number, call))
+        if (!callOnBasicTypes<true, false, true, true>(left_number, right_number, call))
             throw Exception("Wrong call for " + getName() + " with " + col_left.type->getName() + " and " + col_right.type->getName(),
                             ErrorCodes::LOGICAL_ERROR);
     }
@@ -1192,9 +1193,10 @@ public:
         {
             executeTuple(block, result, col_with_type_and_name_left, col_with_type_and_name_right, input_rows_count);
         }
-        else if (isDecimal(left_type) || isDecimal(right_type))
+        else if (isColumnedAsDecimal(left_type) || isColumnedAsDecimal(right_type))
         {
-            if (!allowDecimalComparison(left_type, right_type))
+            // compare
+            if (!allowDecimalComparison(left_type, right_type) && !date_and_datetime)
                 throw Exception("No operation " + getName() + " between " + left_type->getName() + " and " + right_type->getName(),
                     ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 

dbms/src/Functions/FunctionsConversion.cpp

@@ -46,6 +46,7 @@ void registerFunctionsConversion(FunctionFactory & factory)
 
     factory.registerFunction<FunctionToDate>();
     factory.registerFunction<FunctionToDateTime>();
+    factory.registerFunction<FunctionToDateTime64>();
     factory.registerFunction<FunctionToUUID>();
     factory.registerFunction<FunctionToString>();
     factory.registerFunction<FunctionToFixedString>();
@@ -65,6 +66,7 @@ void registerFunctionsConversion(FunctionFactory & factory)
     factory.registerFunction<FunctionToFloat64OrZero>();
     factory.registerFunction<FunctionToDateOrZero>();
     factory.registerFunction<FunctionToDateTimeOrZero>();
+    factory.registerFunction<FunctionToDateTime64OrZero>();
 
     factory.registerFunction<FunctionToDecimal32OrZero>();
     factory.registerFunction<FunctionToDecimal64OrZero>();
@@ -82,6 +84,7 @@ void registerFunctionsConversion(FunctionFactory & factory)
     factory.registerFunction<FunctionToFloat64OrNull>();
     factory.registerFunction<FunctionToDateOrNull>();
     factory.registerFunction<FunctionToDateTimeOrNull>();
+    factory.registerFunction<FunctionToDateTime64OrNull>();
 
     factory.registerFunction<FunctionToDecimal32OrNull>();
     factory.registerFunction<FunctionToDecimal64OrNull>();
@@ -90,6 +93,9 @@ void registerFunctionsConversion(FunctionFactory & factory)
     factory.registerFunction<FunctionParseDateTimeBestEffort>();
     factory.registerFunction<FunctionParseDateTimeBestEffortOrZero>();
     factory.registerFunction<FunctionParseDateTimeBestEffortOrNull>();
+    factory.registerFunction<FunctionParseDateTime64BestEffort>();
+    factory.registerFunction<FunctionParseDateTime64BestEffortOrZero>();
+    factory.registerFunction<FunctionParseDateTime64BestEffortOrNull>();
 
     factory.registerFunction<FunctionConvert<DataTypeInterval, NameToIntervalSecond, PositiveMonotonicity>>();
     factory.registerFunction<FunctionConvert<DataTypeInterval, NameToIntervalMinute, PositiveMonotonicity>>();

dbms/src/Functions/FunctionsConversion.h

@@ -16,6 +16,7 @@
 #include <DataTypes/DataTypeFixedString.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypeEnum.h>
 #include <DataTypes/DataTypeArray.h>
 #include <DataTypes/DataTypeTuple.h>
@@ -106,14 +107,17 @@ struct ConvertImpl
     {
         const ColumnWithTypeAndName & named_from = block.getByPosition(arguments[0]);
 
-        using ColVecFrom = std::conditional_t<IsDecimalNumber<FromFieldType>, ColumnDecimal<FromFieldType>, ColumnVector<FromFieldType>>;
-        using ColVecTo = std::conditional_t<IsDecimalNumber<ToFieldType>, ColumnDecimal<ToFieldType>, ColumnVector<ToFieldType>>;
+        using ColVecFrom = typename FromDataType::ColumnType;
+        using ColVecTo = typename ToDataType::ColumnType;
 
-        if constexpr (IsDataTypeDecimal<FromDataType> || IsDataTypeDecimal<ToDataType>)
+        if constexpr ((IsDataTypeDecimal<FromDataType> || IsDataTypeDecimal<ToDataType>)
+            && !(std::is_same_v<DataTypeDateTime64, FromDataType> || std::is_same_v<DataTypeDateTime64, ToDataType>))
         {
             if constexpr (!IsDataTypeDecimalOrNumber<FromDataType> || !IsDataTypeDecimalOrNumber<ToDataType>)
+            {
                 throw Exception("Illegal column " + named_from.column->getName() + " of first argument of function " + Name::name,
                     ErrorCodes::ILLEGAL_COLUMN);
+            }
         }
 
         if (const ColVecFrom * col_from = checkAndGetColumn<ColVecFrom>(named_from.column.get()))
@@ -155,6 +159,11 @@ struct ConvertImpl
     }
 };
 
+/** Conversion of DateTime to Date: throw off time component.
+  */
+template <typename Name> struct ConvertImpl<DataTypeDateTime, DataTypeDate, Name>
+    : DateTimeTransformImpl<DataTypeDateTime, DataTypeDate, ToDateImpl> {};
+
 
 /** Conversion of Date to DateTime: adding 00:00:00 time component.
   */
@@ -166,11 +175,16 @@ struct ToDateTimeImpl
     {
         return time_zone.fromDayNum(DayNum(d));
     }
+
+    // no-op conversion from DateTime to DateTime, used in DateTime64 to DateTime conversion.
+    static inline UInt32 execute(UInt32 d, const DateLUTImpl & /*time_zone*/)
+    {
+        return d;
+    }
 };
 
 template <typename Name> struct ConvertImpl<DataTypeDate, DataTypeDateTime, Name>
-    : DateTimeTransformImpl<UInt16, UInt32, ToDateTimeImpl> {};
-
+    : DateTimeTransformImpl<DataTypeDate, DataTypeDateTime, ToDateTimeImpl> {};
 
 /// Implementation of toDate function.
 
@@ -185,11 +199,6 @@ struct ToDateTransform32Or64
     }
 };
 
-/** Conversion of DateTime to Date: throw off time component.
-  */
-template <typename Name> struct ConvertImpl<DataTypeDateTime, DataTypeDate, Name>
-    : DateTimeTransformImpl<UInt32, UInt16, ToDateImpl> {};
-
 /** Special case of converting (U)Int32 or (U)Int64 (and also, for convenience, Float32, Float64) to Date.
   * If number is less than 65536, then it is treated as DayNum, and if greater or equals, then as unix timestamp.
   * It's a bit illogical, as we actually have two functions in one.
@@ -198,17 +207,72 @@ template <typename Name> struct ConvertImpl<DataTypeDateTime, DataTypeDate, Name
   *  (otherwise such usage would be frequent mistake).
   */
 template <typename Name> struct ConvertImpl<DataTypeUInt32, DataTypeDate, Name>
-    : DateTimeTransformImpl<UInt32, UInt16, ToDateTransform32Or64<UInt32, UInt16>> {};
+    : DateTimeTransformImpl<DataTypeUInt32, DataTypeDate, ToDateTransform32Or64<UInt32, UInt16>> {};
 template <typename Name> struct ConvertImpl<DataTypeUInt64, DataTypeDate, Name>
-    : DateTimeTransformImpl<UInt64, UInt16, ToDateTransform32Or64<UInt64, UInt16>> {};
+    : DateTimeTransformImpl<DataTypeUInt64, DataTypeDate, ToDateTransform32Or64<UInt64, UInt16>> {};
 template <typename Name> struct ConvertImpl<DataTypeInt32, DataTypeDate, Name>
-    : DateTimeTransformImpl<Int32, UInt16, ToDateTransform32Or64<Int32, UInt16>> {};
+    : DateTimeTransformImpl<DataTypeInt32, DataTypeDate, ToDateTransform32Or64<Int32, UInt16>> {};
 template <typename Name> struct ConvertImpl<DataTypeInt64, DataTypeDate, Name>
-    : DateTimeTransformImpl<Int64, UInt16, ToDateTransform32Or64<Int64, UInt16>> {};
+    : DateTimeTransformImpl<DataTypeInt64, DataTypeDate, ToDateTransform32Or64<Int64, UInt16>> {};
 template <typename Name> struct ConvertImpl<DataTypeFloat32, DataTypeDate, Name>
-    : DateTimeTransformImpl<Float32, UInt16, ToDateTransform32Or64<Float32, UInt16>> {};
+    : DateTimeTransformImpl<DataTypeFloat32, DataTypeDate, ToDateTransform32Or64<Float32, UInt16>> {};
 template <typename Name> struct ConvertImpl<DataTypeFloat64, DataTypeDate, Name>
-    : DateTimeTransformImpl<Float64, UInt16, ToDateTransform32Or64<Float64, UInt16>> {};
+    : DateTimeTransformImpl<DataTypeFloat64, DataTypeDate, ToDateTransform32Or64<Float64, UInt16>> {};
+
+
+/** Conversion of Date or DateTime to DateTime64: add zero sub-second part.
+  */
+struct ToDateTime64Transform
+{
+    static constexpr auto name = "toDateTime64";
+
+    const DateTime64::NativeType scale_multiplier = 1;
+
+    ToDateTime64Transform(UInt32 scale = 0)
+        : scale_multiplier(DecimalUtils::scaleMultiplier<DateTime64::NativeType>(scale))
+    {}
+
+    inline DateTime64::NativeType execute(UInt16 d, const DateLUTImpl & time_zone) const
+    {
+        const auto dt = ToDateTimeImpl::execute(d, time_zone);
+        return execute(dt, time_zone);
+    }
+
+    inline DateTime64::NativeType execute(UInt32 dt, const DateLUTImpl & /*time_zone*/) const
+    {
+        return DecimalUtils::decimalFromComponentsWithMultiplier<DateTime64>(dt, 0, scale_multiplier);
+    }
+};
+
+template <typename Name> struct ConvertImpl<DataTypeDate, DataTypeDateTime64, Name>
+    : DateTimeTransformImpl<DataTypeDate, DataTypeDateTime64, ToDateTime64Transform> {};
+template <typename Name> struct ConvertImpl<DataTypeDateTime, DataTypeDateTime64, Name>
+    : DateTimeTransformImpl<DataTypeDateTime, DataTypeDateTime64, ToDateTime64Transform> {};
+
+/** Conversion of DateTime64 to Date or DateTime: discards fractional part.
+ */
+template <typename Transform>
+struct FromDateTime64Transform
+{
+    static constexpr auto name = Transform::name;
+
+    const DateTime64::NativeType scale_multiplier = 1;
+
+    FromDateTime64Transform(UInt32 scale)
+        : scale_multiplier(DecimalUtils::scaleMultiplier<DateTime64::NativeType>(scale))
+    {}
+
+    inline auto execute(DateTime64::NativeType dt, const DateLUTImpl & time_zone) const
+    {
+        const auto c = DecimalUtils::splitWithScaleMultiplier(DateTime64(dt), scale_multiplier);
+        return Transform::execute(static_cast<UInt32>(c.whole), time_zone);
+    }
+};
+
+template <typename Name> struct ConvertImpl<DataTypeDateTime64, DataTypeDate, Name>
+    : DateTimeTransformImpl<DataTypeDateTime64, DataTypeDate, FromDateTime64Transform<ToDateImpl>> {};
+template <typename Name> struct ConvertImpl<DataTypeDateTime64, DataTypeDateTime, Name>
+    : DateTimeTransformImpl<DataTypeDateTime64, DataTypeDateTime, FromDateTime64Transform<ToDateTimeImpl>> {};
 
 
 /** Transformation of numbers, dates, datetimes to strings: through formatting.
@@ -240,6 +304,16 @@ struct FormatImpl<DataTypeDateTime>
     }
 };
 
+template <>
+struct FormatImpl<DataTypeDateTime64>
+{
+    static void execute(const DataTypeDateTime64::FieldType x, WriteBuffer & wb, const DataTypeDateTime64 * type, const DateLUTImpl * time_zone)
+    {
+        writeDateTimeText(DateTime64(x), type->getScale(), wb, *time_zone);
+    }
+};
+
+
 template <typename FieldType>
 struct FormatImpl<DataTypeEnum<FieldType>>
 {
@@ -284,7 +358,7 @@ struct ConvertImpl<FromDataType, std::enable_if_t<!std::is_same_v<FromDataType,
         const DateLUTImpl * time_zone = nullptr;
 
         /// For argument of DateTime type, second argument with time zone could be specified.
-        if constexpr (std::is_same_v<FromDataType, DataTypeDateTime>)
+        if constexpr (std::is_same_v<FromDataType, DataTypeDateTime> || std::is_same_v<FromDataType, DataTypeDateTime64>)
             time_zone = &extractTimeZoneFromFunctionArguments(block, arguments, 1, 0);
 
         if (const auto col_from = checkAndGetColumn<ColVecType>(col_with_type_and_name.column.get()))
@@ -300,6 +374,8 @@ struct ConvertImpl<FromDataType, std::enable_if_t<!std::is_same_v<FromDataType,
                 data_to.resize(size * (strlen("YYYY-MM-DD") + 1));
             else if constexpr (std::is_same_v<FromDataType, DataTypeDateTime>)
                 data_to.resize(size * (strlen("YYYY-MM-DD hh:mm:ss") + 1));
+            else if constexpr (std::is_same_v<FromDataType, DataTypeDateTime64>)
+                data_to.resize(size * (strlen("YYYY-MM-DD hh:mm:ss.") + vec_from.getScale() + 1));
             else
                 data_to.resize(size * 3);   /// Arbitary
 
@@ -448,6 +524,8 @@ struct ConvertThroughParsing
     static_assert(std::is_same_v<FromDataType, DataTypeString> || std::is_same_v<FromDataType, DataTypeFixedString>,
         "ConvertThroughParsing is only applicable for String or FixedString data types");
 
+    static constexpr bool to_datetime64 = std::is_same_v<ToDataType, DataTypeDateTime64>;
+
     using ToFieldType = typename ToDataType::FieldType;
 
     static bool isAllRead(ReadBuffer & in)
@@ -471,15 +549,22 @@ struct ConvertThroughParsing
     static void execute(Block & block, const ColumnNumbers & arguments, size_t result, size_t input_rows_count,
                         Additions additions [[maybe_unused]] = Additions())
     {
-        using ColVecTo = std::conditional_t<IsDecimalNumber<ToFieldType>, ColumnDecimal<ToFieldType>, ColumnVector<ToFieldType>>;
+        using ColVecTo = typename ToDataType::ColumnType;
 
         const DateLUTImpl * local_time_zone [[maybe_unused]] = nullptr;
         const DateLUTImpl * utc_time_zone [[maybe_unused]] = nullptr;
 
         /// For conversion to DateTime type, second argument with time zone could be specified.
-        if constexpr (std::is_same_v<ToDataType, DataTypeDateTime>)
+        if constexpr (std::is_same_v<ToDataType, DataTypeDateTime> || to_datetime64)
         {
-            local_time_zone = &extractTimeZoneFromFunctionArguments(block, arguments, 1, 0);
+            const auto result_type = removeNullable(block.getByPosition(result).type);
+            // Time zone is already figured out during result type resultion, no need to do it here.
+            if (const auto dt_col = checkAndGetDataType<ToDataType>(result_type.get()))
+                local_time_zone = &dt_col->getTimeZone();
+            else
+            {
+                local_time_zone = &extractTimeZoneFromFunctionArguments(block, arguments, 1, 0);
+            }
 
             if constexpr (parsing_mode == ConvertFromStringParsingMode::BestEffort)
                 utc_time_zone = &DateLUT::instance("UTC");
@@ -505,7 +590,14 @@ struct ConvertThroughParsing
         if constexpr (IsDataTypeDecimal<ToDataType>)
         {
             UInt32 scale = additions;
-            ToDataType check_bounds_in_ctor(ToDataType::maxPrecision(), scale);
+            if constexpr (to_datetime64)
+            {
+                ToDataType check_bounds_in_ctor(scale, local_time_zone ? local_time_zone->getTimeZone() : String{});
+            }
+            else
+            {
+                ToDataType check_bounds_in_ctor(ToDataType::maxPrecision(), scale);
+            }
             col_to = ColVecTo::create(size, scale);
         }
         else
@@ -549,13 +641,28 @@ struct ConvertThroughParsing
             {
                 if constexpr (parsing_mode == ConvertFromStringParsingMode::BestEffort)
                 {
-                    time_t res;
-                    parseDateTimeBestEffort(res, read_buffer, *local_time_zone, *utc_time_zone);
-                    vec_to[i] = res;
+                    if constexpr (to_datetime64)
+                    {
+                        DateTime64 res = 0;
+                        parseDateTime64BestEffort(res, vec_to.getScale(), read_buffer, *local_time_zone, *utc_time_zone);
+                        vec_to[i] = res;
+                    }
+                    else
+                    {
+                        time_t res;
+                        parseDateTimeBestEffort(res, read_buffer, *local_time_zone, *utc_time_zone);
+                        vec_to[i] = res;
+                    }
                 }
                 else
                 {
-                    if constexpr (IsDataTypeDecimal<ToDataType>)
+                    if constexpr (to_datetime64)
+                    {
+                        DateTime64 value = 0;
+                        readDateTime64Text(value, vec_to.getScale(), read_buffer, *local_time_zone);
+                        vec_to[i] = value;
+                    }
+                    else if constexpr (IsDataTypeDecimal<ToDataType>)
                         ToDataType::readText(vec_to[i], read_buffer, ToDataType::maxPrecision(), vec_to.getScale());
                     else
                         parseImpl<ToDataType>(vec_to[i], read_buffer, local_time_zone);
@@ -570,13 +677,28 @@ struct ConvertThroughParsing
 
                 if constexpr (parsing_mode == ConvertFromStringParsingMode::BestEffort)
                 {
-                    time_t res;
-                    parsed = tryParseDateTimeBestEffort(res, read_buffer, *local_time_zone, *utc_time_zone);
-                    vec_to[i] = res;
+                    if constexpr (to_datetime64)
+                    {
+                        DateTime64 res = 0;
+                        parsed = tryParseDateTime64BestEffort(res, vec_to.getScale(), read_buffer, *local_time_zone, *utc_time_zone);
+                        vec_to[i] = res;
+                    }
+                    else
+                    {
+                        time_t res;
+                        parsed = tryParseDateTimeBestEffort(res, read_buffer, *local_time_zone, *utc_time_zone);
+                        vec_to[i] = res;
+                    }
                 }
                 else
                 {
-                    if constexpr (IsDataTypeDecimal<ToDataType>)
+                    if constexpr (to_datetime64)
+                    {
+                        DateTime64 value = 0;
+                        parsed = tryReadDateTime64Text(value, vec_to.getScale(), read_buffer, *local_time_zone);
+                        vec_to[i] = value;
+                    }
+                    else if constexpr (IsDataTypeDecimal<ToDataType>)
                         parsed = ToDataType::tryReadText(vec_to[i], read_buffer, ToDataType::maxPrecision(), vec_to.getScale());
                     else
                         parsed = tryParseImpl<ToDataType>(vec_to[i], read_buffer, local_time_zone);
@@ -725,6 +847,7 @@ struct ConvertImpl<DataTypeFixedString, DataTypeString, Name>
 /// Declared early because used below.
 struct NameToDate { static constexpr auto name = "toDate"; };
 struct NameToDateTime { static constexpr auto name = "toDateTime"; };
+struct NameToDateTime64 { static constexpr auto name = "toDateTime64"; };
 struct NameToString { static constexpr auto name = "toString"; };
 struct NameToDecimal32 { static constexpr auto name = "toDecimal32"; };
 struct NameToDecimal64 { static constexpr auto name = "toDecimal64"; };
@@ -760,6 +883,8 @@ public:
     static constexpr bool to_decimal =
         std::is_same_v<Name, NameToDecimal32> || std::is_same_v<Name, NameToDecimal64> || std::is_same_v<Name, NameToDecimal128>;
 
+    static constexpr bool to_datetime64 = std::is_same_v<ToDataType, DataTypeDateTime64>;
+
     static FunctionPtr create(const Context &) { return std::make_shared<FunctionConvert>(); }
 
     String getName() const override
@@ -773,16 +898,19 @@ public:
 
     DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
     {
-        if (to_decimal && arguments.size() != 2)
+        FunctionArgumentTypeValidators mandatory_args = {{[](const auto &) {return true;}, "ANY TYPE"}};
+        FunctionArgumentTypeValidators optional_args;
+
+        if constexpr (to_decimal || to_datetime64)
         {
-            throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
-                + toString(arguments.size()) + ", should be 2.",
-                ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
+            mandatory_args.push_back(FunctionArgumentTypeValidator{&isNativeInteger, "Integer"}); // scale
         }
-        else if (arguments.size() != 1 && arguments.size() != 2)
-            throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
-                + toString(arguments.size()) + ", should be 1 or 2. Second argument (time zone) is optional only make sense for DateTime.",
-                ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
+        else
+        {
+            optional_args.push_back(FunctionArgumentTypeValidator{&isString, "String"}); // timezone
+        }
+
+        validateFunctionArgumentTypes(*this, arguments, mandatory_args, optional_args);
 
         if constexpr (std::is_same_v<ToDataType, DataTypeInterval>)
         {
@@ -796,42 +924,31 @@ public:
             UInt64 scale = extractToDecimalScale(arguments[1]);
 
             if constexpr (std::is_same_v<Name, NameToDecimal32>)
-                return createDecimal(9, scale);
+                return createDecimal<DataTypeDecimal>(9, scale);
             else if constexpr (std::is_same_v<Name, NameToDecimal64>)
-                return createDecimal(18, scale);
+                return createDecimal<DataTypeDecimal>(18, scale);
             else if constexpr (std::is_same_v<Name, NameToDecimal128>)
-                return createDecimal(38, scale);
+                return createDecimal<DataTypeDecimal>(38, scale);
 
             throw Exception("Someting wrong with toDecimalNN()", ErrorCodes::LOGICAL_ERROR);
         }
         else
         {
-            /** Optional second argument with time zone is supported:
-              * - for functions toDateTime, toUnixTimestamp, toDate;
-              * - for function toString of DateTime argument.
-              */
+            // Optional second argument with time zone for DateTime.
+            UInt8 timezone_arg_position = 1;
+            UInt32 scale [[maybe_unused]] = DataTypeDateTime64::default_scale;
 
-            if (arguments.size() == 2)
+            // DateTime64 requires more arguments: scale and timezone. Since timezone is optional, scale should be first.
+            if constexpr (to_datetime64)
             {
-                if (!checkAndGetDataType<DataTypeString>(arguments[1].type.get()))
-                    throw Exception("Illegal type " + arguments[1].type->getName() + " of 2nd argument of function " + getName(),
-                        ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-
-                static constexpr bool to_date_or_time = std::is_same_v<Name, NameToDateTime>
-                    || std::is_same_v<Name, NameToDate>
-                    || std::is_same_v<Name, NameToUnixTimestamp>;
-
-                if (!(to_date_or_time
-                    || (std::is_same_v<Name, NameToString> && WhichDataType(arguments[0].type).isDateTime())))
-                {
-                    throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
-                        + toString(arguments.size()) + ", should be 1.",
-                        ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
-                }
+                timezone_arg_position += 1;
+                scale = static_cast<UInt32>(arguments[1].column->get64(0));
             }
 
-            if (std::is_same_v<ToDataType, DataTypeDateTime>)
-                return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, 1, 0));
+            if constexpr (std::is_same_v<ToDataType, DataTypeDateTime>)
+                return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, timezone_arg_position, 0));
+            else if constexpr (to_datetime64)
+                return std::make_shared<DataTypeDateTime64>(scale, extractTimeZoneNameFromFunctionArguments(arguments, timezone_arg_position, 0));
             else
                 return std::make_shared<ToDataType>();
         }
@@ -902,17 +1019,32 @@ private:
 
             if constexpr (IsDataTypeDecimal<RightDataType>)
             {
-                if (arguments.size() != 2)
+                if constexpr (std::is_same_v<RightDataType, DataTypeDateTime64>)
+                {
+                    // account for optional timezone argument
+                    if (arguments.size() != 2 && arguments.size() != 3)
+                        throw Exception{"Function " + getName() + " expects 2 or 3 arguments for DataTypeDateTime64.",
+                            ErrorCodes::TOO_FEW_ARGUMENTS_FOR_FUNCTION};
+                }
+                else if (arguments.size() != 2)
+                {
                     throw Exception{"Function " + getName() + " expects 2 arguments for Decimal.",
                         ErrorCodes::TOO_FEW_ARGUMENTS_FOR_FUNCTION};
+                }
 
                 const ColumnWithTypeAndName & scale_column = block.getByPosition(arguments[1]);
                 UInt32 scale = extractToDecimalScale(scale_column);
 
                 ConvertImpl<LeftDataType, RightDataType, Name>::execute(block, arguments, result, input_rows_count, scale);
             }
+            else if constexpr (IsDataTypeDateOrDateTime<RightDataType> && std::is_same_v<LeftDataType, DataTypeDateTime64>)
+            {
+                const auto * dt64 = assert_cast<const DataTypeDateTime64 *>(block.getByPosition(arguments[0]).type.get());
+                ConvertImpl<LeftDataType, RightDataType, Name>::execute(block, arguments, result, input_rows_count, dt64->getScale());
+            }
             else
                 ConvertImpl<LeftDataType, RightDataType, Name>::execute(block, arguments, result, input_rows_count);
+
             return true;
         };
 
@@ -1015,15 +1147,23 @@ public:
             UInt64 scale = extractToDecimalScale(arguments[1]);
 
             if constexpr (std::is_same_v<ToDataType, DataTypeDecimal<Decimal32>>)
-                res = createDecimal(9, scale);
+                res = createDecimal<DataTypeDecimal>(9, scale);
             else if constexpr (std::is_same_v<ToDataType, DataTypeDecimal<Decimal64>>)
-                res = createDecimal(18, scale);
+                res = createDecimal<DataTypeDecimal>(18, scale);
             else if constexpr (std::is_same_v<ToDataType, DataTypeDecimal<Decimal128>>)
-                res = createDecimal(38, scale);
+                res = createDecimal<DataTypeDecimal>(38, scale);
 
             if (!res)
                 throw Exception("Someting wrong with toDecimalNNOrZero() or toDecimalNNOrNull()", ErrorCodes::LOGICAL_ERROR);
         }
+        else if constexpr (std::is_same_v<ToDataType, DataTypeDateTime64>)
+        {
+            UInt64 scale = DataTypeDateTime64::default_scale;
+            if (arguments.size() > 1)
+                scale = extractToDecimalScale(arguments[1]);
+            const auto timezone = extractTimeZoneNameFromFunctionArguments(arguments, 2, 0);
+            res = std::make_shared<DataTypeDateTime64>(scale, timezone);
+        }
         else
             res = std::make_shared<ToDataType>();
 
@@ -1038,7 +1178,7 @@ public:
         const IDataType * from_type = block.getByPosition(arguments[0]).type.get();
 
         bool ok = true;
-        if constexpr (to_decimal)
+        if constexpr (to_decimal || std::is_same_v<ToDataType, DataTypeDateTime64>)
         {
             if (arguments.size() != 2)
                 throw Exception{"Function " + getName() + " expects 2 arguments for Decimal.", ErrorCodes::TOO_FEW_ARGUMENTS_FOR_FUNCTION};
@@ -1380,6 +1520,7 @@ using FunctionToFloat32 = FunctionConvert<DataTypeFloat32, NameToFloat32, ToNumb
 using FunctionToFloat64 = FunctionConvert<DataTypeFloat64, NameToFloat64, ToNumberMonotonicity<Float64>>;
 using FunctionToDate = FunctionConvert<DataTypeDate, NameToDate, ToNumberMonotonicity<UInt16>>;
 using FunctionToDateTime = FunctionConvert<DataTypeDateTime, NameToDateTime, ToNumberMonotonicity<UInt32>>;
+using FunctionToDateTime64 = FunctionConvert<DataTypeDateTime64, NameToDateTime64, UnknownMonotonicity>;
 using FunctionToUUID = FunctionConvert<DataTypeUUID, NameToUUID, ToNumberMonotonicity<UInt128>>;
 using FunctionToString = FunctionConvert<DataTypeString, NameToString, ToStringMonotonicity>;
 using FunctionToUnixTimestamp = FunctionConvert<DataTypeUInt32, NameToUnixTimestamp, ToNumberMonotonicity<UInt32>>;
@@ -1402,6 +1543,7 @@ template <> struct FunctionTo<DataTypeFloat32> { using Type = FunctionToFloat32;
 template <> struct FunctionTo<DataTypeFloat64> { using Type = FunctionToFloat64; };
 template <> struct FunctionTo<DataTypeDate> { using Type = FunctionToDate; };
 template <> struct FunctionTo<DataTypeDateTime> { using Type = FunctionToDateTime; };
+template <> struct FunctionTo<DataTypeDateTime64> { using Type = FunctionToDateTime64; };
 template <> struct FunctionTo<DataTypeUUID> { using Type = FunctionToUUID; };
 template <> struct FunctionTo<DataTypeString> { using Type = FunctionToString; };
 template <> struct FunctionTo<DataTypeFixedString> { using Type = FunctionToFixedString; };
@@ -1426,6 +1568,7 @@ struct NameToFloat32OrZero { static constexpr auto name = "toFloat32OrZero"; };
 struct NameToFloat64OrZero { static constexpr auto name = "toFloat64OrZero"; };
 struct NameToDateOrZero { static constexpr auto name = "toDateOrZero"; };
 struct NameToDateTimeOrZero { static constexpr auto name = "toDateTimeOrZero"; };
+struct NameToDateTime64OrZero { static constexpr auto name = "toDateTime64OrZero"; };
 struct NameToDecimal32OrZero { static constexpr auto name = "toDecimal32OrZero"; };
 struct NameToDecimal64OrZero { static constexpr auto name = "toDecimal64OrZero"; };
 struct NameToDecimal128OrZero { static constexpr auto name = "toDecimal128OrZero"; };
@@ -1442,6 +1585,7 @@ using FunctionToFloat32OrZero = FunctionConvertFromString<DataTypeFloat32, NameT
 using FunctionToFloat64OrZero = FunctionConvertFromString<DataTypeFloat64, NameToFloat64OrZero, ConvertFromStringExceptionMode::Zero>;
 using FunctionToDateOrZero = FunctionConvertFromString<DataTypeDate, NameToDateOrZero, ConvertFromStringExceptionMode::Zero>;
 using FunctionToDateTimeOrZero = FunctionConvertFromString<DataTypeDateTime, NameToDateTimeOrZero, ConvertFromStringExceptionMode::Zero>;
+using FunctionToDateTime64OrZero = FunctionConvertFromString<DataTypeDateTime64, NameToDateTime64OrZero, ConvertFromStringExceptionMode::Zero>;
 using FunctionToDecimal32OrZero = FunctionConvertFromString<DataTypeDecimal<Decimal32>, NameToDecimal32OrZero, ConvertFromStringExceptionMode::Zero>;
 using FunctionToDecimal64OrZero = FunctionConvertFromString<DataTypeDecimal<Decimal64>, NameToDecimal64OrZero, ConvertFromStringExceptionMode::Zero>;
 using FunctionToDecimal128OrZero = FunctionConvertFromString<DataTypeDecimal<Decimal128>, NameToDecimal128OrZero, ConvertFromStringExceptionMode::Zero>;
@@ -1458,6 +1602,7 @@ struct NameToFloat32OrNull { static constexpr auto name = "toFloat32OrNull"; };
 struct NameToFloat64OrNull { static constexpr auto name = "toFloat64OrNull"; };
 struct NameToDateOrNull { static constexpr auto name = "toDateOrNull"; };
 struct NameToDateTimeOrNull { static constexpr auto name = "toDateTimeOrNull"; };
+struct NameToDateTime64OrNull { static constexpr auto name = "toDateTime64OrNull"; };
 struct NameToDecimal32OrNull { static constexpr auto name = "toDecimal32OrNull"; };
 struct NameToDecimal64OrNull { static constexpr auto name = "toDecimal64OrNull"; };
 struct NameToDecimal128OrNull { static constexpr auto name = "toDecimal128OrNull"; };
@@ -1474,6 +1619,7 @@ using FunctionToFloat32OrNull = FunctionConvertFromString<DataTypeFloat32, NameT
 using FunctionToFloat64OrNull = FunctionConvertFromString<DataTypeFloat64, NameToFloat64OrNull, ConvertFromStringExceptionMode::Null>;
 using FunctionToDateOrNull = FunctionConvertFromString<DataTypeDate, NameToDateOrNull, ConvertFromStringExceptionMode::Null>;
 using FunctionToDateTimeOrNull = FunctionConvertFromString<DataTypeDateTime, NameToDateTimeOrNull, ConvertFromStringExceptionMode::Null>;
+using FunctionToDateTime64OrNull = FunctionConvertFromString<DataTypeDateTime64, NameToDateTime64OrNull, ConvertFromStringExceptionMode::Null>;
 using FunctionToDecimal32OrNull = FunctionConvertFromString<DataTypeDecimal<Decimal32>, NameToDecimal32OrNull, ConvertFromStringExceptionMode::Null>;
 using FunctionToDecimal64OrNull = FunctionConvertFromString<DataTypeDecimal<Decimal64>, NameToDecimal64OrNull, ConvertFromStringExceptionMode::Null>;
 using FunctionToDecimal128OrNull = FunctionConvertFromString<DataTypeDecimal<Decimal128>, NameToDecimal128OrNull, ConvertFromStringExceptionMode::Null>;
@@ -1481,6 +1627,10 @@ using FunctionToDecimal128OrNull = FunctionConvertFromString<DataTypeDecimal<Dec
 struct NameParseDateTimeBestEffort { static constexpr auto name = "parseDateTimeBestEffort"; };
 struct NameParseDateTimeBestEffortOrZero { static constexpr auto name = "parseDateTimeBestEffortOrZero"; };
 struct NameParseDateTimeBestEffortOrNull { static constexpr auto name = "parseDateTimeBestEffortOrNull"; };
+struct NameParseDateTime64BestEffort { static constexpr auto name = "parseDateTime64BestEffort"; };
+struct NameParseDateTime64BestEffortOrZero { static constexpr auto name = "parseDateTime64BestEffortOrZero"; };
+struct NameParseDateTime64BestEffortOrNull { static constexpr auto name = "parseDateTime64BestEffortOrNull"; };
+
 
 using FunctionParseDateTimeBestEffort = FunctionConvertFromString<
     DataTypeDateTime, NameParseDateTimeBestEffort, ConvertFromStringExceptionMode::Throw, ConvertFromStringParsingMode::BestEffort>;
@@ -1489,6 +1639,12 @@ using FunctionParseDateTimeBestEffortOrZero = FunctionConvertFromString<
 using FunctionParseDateTimeBestEffortOrNull = FunctionConvertFromString<
     DataTypeDateTime, NameParseDateTimeBestEffortOrNull, ConvertFromStringExceptionMode::Null, ConvertFromStringParsingMode::BestEffort>;
 
+using FunctionParseDateTime64BestEffort = FunctionConvertFromString<
+    DataTypeDateTime64, NameParseDateTime64BestEffort, ConvertFromStringExceptionMode::Throw, ConvertFromStringParsingMode::BestEffort>;
+using FunctionParseDateTime64BestEffortOrZero = FunctionConvertFromString<
+    DataTypeDateTime64, NameParseDateTime64BestEffortOrZero, ConvertFromStringExceptionMode::Zero, ConvertFromStringParsingMode::BestEffort>;
+using FunctionParseDateTime64BestEffortOrNull = FunctionConvertFromString<
+    DataTypeDateTime64, NameParseDateTime64BestEffortOrNull, ConvertFromStringExceptionMode::Null, ConvertFromStringParsingMode::BestEffort>;
 
 class PreparedFunctionCast : public PreparedFunctionImpl
 {
@@ -1639,13 +1795,11 @@ private:
         };
     }
 
-    template <typename FieldType>
-    WrapperType createDecimalWrapper(const DataTypePtr & from_type, const DataTypeDecimal<FieldType> * to_type) const
+    template <typename ToDataType>
+    std::enable_if_t<IsDataTypeDecimal<ToDataType>, WrapperType>
+    createDecimalWrapper(const DataTypePtr & from_type, const ToDataType * to_type) const
     {
-        using ToDataType = DataTypeDecimal<FieldType>;
-
         TypeIndex type_index = from_type->getTypeId();
-        UInt32 precision = to_type->getPrecision();
         UInt32 scale = to_type->getScale();
 
         WhichDataType which(type_index);
@@ -1659,7 +1813,7 @@ private:
             throw Exception{"Conversion from " + from_type->getName() + " to " + to_type->getName() + " is not supported",
                 ErrorCodes::CANNOT_CONVERT_TYPE};
 
-        return [type_index, precision, scale] (Block & block, const ColumnNumbers & arguments, const size_t result, size_t input_rows_count)
+        return [type_index, scale, to_type] (Block & block, const ColumnNumbers & arguments, const size_t result, size_t input_rows_count)
         {
             auto res = callOnIndexAndDataType<ToDataType>(type_index, [&](const auto & types) -> bool
             {
@@ -1674,8 +1828,7 @@ private:
             /// Additionally check if callOnIndexAndDataType wasn't called at all.
             if (!res)
             {
-                auto to = DataTypeDecimal<FieldType>(precision, scale);
-                throw Exception{"Conversion from " + std::string(getTypeName(type_index)) + " to " + to.getName() +
+                throw Exception{"Conversion from " + std::string(getTypeName(type_index)) + " to " + to_type->getName() +
                                 " is not supported", ErrorCodes::CANNOT_CONVERT_TYPE};
             }
         };
@@ -2140,7 +2293,8 @@ private:
             if constexpr (
                 std::is_same_v<ToDataType, DataTypeDecimal<Decimal32>> ||
                 std::is_same_v<ToDataType, DataTypeDecimal<Decimal64>> ||
-                std::is_same_v<ToDataType, DataTypeDecimal<Decimal128>>)
+                std::is_same_v<ToDataType, DataTypeDecimal<Decimal128>> ||
+                std::is_same_v<ToDataType, DataTypeDateTime64>)
             {
                 ret = createDecimalWrapper(from_type, checkAndGetDataType<ToDataType>(to_type.get()));
                 return true;

dbms/src/Functions/FunctionsReinterpret.h

@@ -5,10 +5,12 @@
 #include <DataTypes/DataTypeFixedString.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <Columns/ColumnString.h>
 #include <Columns/ColumnFixedString.h>
 #include <Columns/ColumnConst.h>
 #include <Columns/ColumnVector.h>
+#include <Columns/ColumnDecimal.h>
 #include <Common/typeid_cast.h>
 #include <Common/memcpySmall.h>
 #include <Functions/IFunction.h>
@@ -147,7 +149,6 @@ public:
     }
 };
 
-
 template <typename ToDataType, typename Name>
 class FunctionReinterpretStringAs : public IFunction
 {
@@ -156,6 +157,7 @@ public:
     static FunctionPtr create(const Context &) { return std::make_shared<FunctionReinterpretStringAs>(); }
 
     using ToFieldType = typename ToDataType::FieldType;
+    using ColumnType = typename ToDataType::ColumnType;
 
     String getName() const override
     {
@@ -179,12 +181,12 @@ public:
     {
         if (const ColumnString * col_from = typeid_cast<const ColumnString *>(block.getByPosition(arguments[0]).column.get()))
         {
-            auto col_res = ColumnVector<ToFieldType>::create();
+            auto col_res = ColumnType::create();
 
             const ColumnString::Chars & data_from = col_from->getChars();
             const ColumnString::Offsets & offsets_from = col_from->getOffsets();
             size_t size = offsets_from.size();
-            typename ColumnVector<ToFieldType>::Container & vec_res = col_res->getData();
+            typename ColumnType::Container & vec_res = col_res->getData();
             vec_res.resize(size);
 
             size_t offset = 0;

dbms/src/Functions/FunctionsRound.h

@@ -6,6 +6,7 @@
 #include <DataTypes/DataTypeArray.h>
 #include <DataTypes/DataTypesNumber.h>
 #include <DataTypes/DataTypesDecimal.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <Columns/ColumnVector.h>
 #include <Interpreters/castColumn.h>
 #include "IFunction.h"

dbms/src/Functions/array/arrayCumSum.cpp

@@ -36,7 +36,7 @@ struct ArrayCumSumImpl
         if (which.isDecimal())
         {
             UInt32 scale = getDecimalScale(*expression_return);
-            DataTypePtr nested = std::make_shared<DataTypeDecimal<Decimal128>>(maxDecimalPrecision<Decimal128>(), scale);
+            DataTypePtr nested = std::make_shared<DataTypeDecimal<Decimal128>>(DecimalUtils::maxPrecision<Decimal128>(), scale);
             return std::make_shared<DataTypeArray>(nested);
         }
 

dbms/src/Functions/array/arrayCumSumNonNegative.cpp

@@ -39,7 +39,7 @@ struct ArrayCumSumNonNegativeImpl
         if (which.isDecimal())
         {
             UInt32 scale = getDecimalScale(*expression_return);
-            DataTypePtr nested = std::make_shared<DataTypeDecimal<Decimal128>>(maxDecimalPrecision<Decimal128>(), scale);
+            DataTypePtr nested = std::make_shared<DataTypeDecimal<Decimal128>>(DecimalUtils::maxPrecision<Decimal128>(), scale);
             return std::make_shared<DataTypeArray>(nested);
         }
 

dbms/src/Functions/array/arrayIntersect.cpp

@@ -7,6 +7,7 @@
 #include <DataTypes/DataTypesDecimal.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypeNullable.h>
 #include <DataTypes/DataTypeTuple.h>
 #include <DataTypes/getMostSubtype.h>

dbms/src/Functions/array/arraySum.cpp

@@ -36,7 +36,7 @@ struct ArraySumImpl
         if (which.isDecimal())
         {
             UInt32 scale = getDecimalScale(*expression_return);
-            return std::make_shared<DataTypeDecimal<Decimal128>>(maxDecimalPrecision<Decimal128>(), scale);
+            return std::make_shared<DataTypeDecimal<Decimal128>>(DecimalUtils::maxPrecision<Decimal128>(), scale);
         }
 
         throw Exception("arraySum cannot add values of type " + expression_return->getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

dbms/src/Functions/array/emptyArray.cpp

@@ -4,6 +4,7 @@
 #include <DataTypes/DataTypesNumber.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypeString.h>
 #include <Columns/ColumnArray.h>
 #include <Columns/ColumnString.h>

dbms/src/Functions/dateDiff.cpp

@@ -1,4 +1,5 @@
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypesNumber.h>
 #include <Columns/ColumnString.h>
 #include <Columns/ColumnsNumber.h>

dbms/src/Functions/extractTimeZoneFromFunctionArguments.cpp

@@ -2,6 +2,7 @@
 #include <Functions/FunctionHelpers.h>
 #include <Core/Block.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <Columns/ColumnString.h>
 #include <common/DateLUT.h>
 
@@ -43,6 +44,8 @@ std::string extractTimeZoneNameFromFunctionArguments(const ColumnsWithTypeAndNam
         /// If time zone is attached to an argument of type DateTime.
         if (const DataTypeDateTime * type = checkAndGetDataType<DataTypeDateTime>(arguments[datetime_arg_num].type.get()))
             return type->getTimeZone().getTimeZone();
+        if (const DataTypeDateTime64 * type = checkAndGetDataType<DataTypeDateTime64>(arguments[datetime_arg_num].type.get()))
+            return type->getTimeZone().getTimeZone();
 
         return {};
     }

dbms/src/Functions/formatDateTime.cpp

@@ -1,4 +1,7 @@
 #include <DataTypes/DataTypeString.h>
+#include <DataTypes/DataTypeDate.h>
+#include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <Columns/ColumnString.h>
 
 #include <Functions/IFunction.h>
@@ -11,6 +14,7 @@
 
 #include <common/DateLUTImpl.h>
 #include <common/find_symbols.h>
+#include <Core/DecimalFunctions.h>
 
 #include <type_traits>
 
@@ -27,6 +31,16 @@ namespace ErrorCodes
     extern const int BAD_ARGUMENTS;
 }
 
+namespace
+{
+// in private namespace to avoid GCC 9 error: "explicit specialization in non-namespace scope"
+template <typename DataType> struct ActionaValueTypeMap {};
+template <> struct ActionaValueTypeMap<DataTypeDate>       { using ActionValueType = UInt16; };
+template <> struct ActionaValueTypeMap<DataTypeDateTime>   { using ActionValueType = UInt32; };
+// TODO(vnemkov): once there is support for Int64 in LUT, make that Int64.
+// TODO(vnemkov): to add sub-second format instruction, make that DateTime64 and do some math in Action<T>.
+template <> struct ActionaValueTypeMap<DataTypeDateTime64> { using ActionValueType = UInt32; };
+}
 
 /** formatDateTime(time, 'pattern')
   * Performs formatting of time, according to provided pattern.
@@ -270,86 +284,105 @@ public:
 
     void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override
     {
-        if (!executeType<UInt32>(block, arguments, result)
-            && !executeType<UInt16>(block, arguments, result))
+        if (!executeType<DataTypeDate>(block, arguments, result)
+            && !executeType<DataTypeDateTime>(block, arguments, result)
+            && !executeType<DataTypeDateTime64>(block, arguments, result))
             throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
                             + " of function " + getName() + ", must be Date or DateTime",
                             ErrorCodes::ILLEGAL_COLUMN);
     }
 
-    template <typename T>
+    template <typename DataType>
     bool executeType(Block & block, const ColumnNumbers & arguments, size_t result)
     {
-        if (auto * times = checkAndGetColumn<ColumnVector<T>>(block.getByPosition(arguments[0]).column.get()))
+        auto * times = checkAndGetColumn<typename DataType::ColumnType>(block.getByPosition(arguments[0]).column.get());
+        if (!times)
+            return false;
+
+        const ColumnConst * pattern_column = checkAndGetColumnConst<ColumnString>(block.getByPosition(arguments[1]).column.get());
+        if (!pattern_column)
+            throw Exception("Illegal column " + block.getByPosition(arguments[1]).column->getName()
+                            + " of second ('format') argument of function " + getName()
+                            + ". Must be constant string.",
+                            ErrorCodes::ILLEGAL_COLUMN);
+
+        String pattern = pattern_column->getValue<String>();
+
+        using T = typename ActionaValueTypeMap<DataType>::ActionValueType;
+        std::vector<Action<T>> instructions;
+        String pattern_to_fill = parsePattern(pattern, instructions);
+        size_t result_size = pattern_to_fill.size();
+
+        const DateLUTImpl * time_zone_tmp = nullptr;
+        if (arguments.size() == 3)
+            time_zone_tmp = &extractTimeZoneFromFunctionArguments(block, arguments, 2, 0);
+        else
+            time_zone_tmp = &DateLUT::instance();
+
+        const DateLUTImpl & time_zone = *time_zone_tmp;
+
+        const auto & vec = times->getData();
+
+        UInt32 scale [[maybe_unused]] = 0;
+        if constexpr (std::is_same_v<DataType, DataTypeDateTime64>)
         {
-            const ColumnConst * pattern_column = checkAndGetColumnConst<ColumnString>(block.getByPosition(arguments[1]).column.get());
+            scale = vec.getScale();
+        }
 
-            if (!pattern_column)
-                throw Exception("Illegal column " + block.getByPosition(arguments[1]).column->getName()
-                                + " of second ('format') argument of function " + getName()
-                                + ". Must be constant string.",
-                                ErrorCodes::ILLEGAL_COLUMN);
+        auto col_res = ColumnString::create();
+        auto & dst_data = col_res->getChars();
+        auto & dst_offsets = col_res->getOffsets();
+        dst_data.resize(vec.size() * (result_size + 1));
+        dst_offsets.resize(vec.size());
 
-            String pattern = pattern_column->getValue<String>();
+        /// Fill result with literals.
+        {
+            UInt8 * begin = dst_data.data();
+            UInt8 * end = begin + dst_data.size();
+            UInt8 * pos = begin;
 
-            std::vector<Action<T>> instructions;
-            String pattern_to_fill = parsePattern(pattern, instructions);
-            size_t result_size = pattern_to_fill.size();
-
-            const DateLUTImpl * time_zone_tmp = nullptr;
-            if (arguments.size() == 3)
-                time_zone_tmp = &extractTimeZoneFromFunctionArguments(block, arguments, 2, 0);
-            else
-                time_zone_tmp = &DateLUT::instance();
-
-            const DateLUTImpl & time_zone = *time_zone_tmp;
-
-            const typename ColumnVector<T>::Container & vec = times->getData();
-
-            auto col_res = ColumnString::create();
-            auto & dst_data = col_res->getChars();
-            auto & dst_offsets = col_res->getOffsets();
-            dst_data.resize(vec.size() * (result_size + 1));
-            dst_offsets.resize(vec.size());
-
-            /// Fill result with literals.
+            if (pos < end)
             {
-                UInt8 * begin = dst_data.data();
-                UInt8 * end = begin + dst_data.size();
-                UInt8 * pos = begin;
-
-                if (pos < end)
-                {
-                    memcpy(pos, pattern_to_fill.data(), result_size + 1);   /// With zero terminator.
-                    pos += result_size + 1;
-                }
-
-                /// Fill by copying exponential growing ranges.
-                while (pos < end)
-                {
-                    size_t bytes_to_copy = std::min(pos - begin, end - pos);
-                    memcpy(pos, begin, bytes_to_copy);
-                    pos += bytes_to_copy;
-                }
+                memcpy(pos, pattern_to_fill.data(), result_size + 1);   /// With zero terminator.
+                pos += result_size + 1;
             }
 
-            auto begin = reinterpret_cast<char *>(dst_data.data());
-            auto pos = begin;
+            /// Fill by copying exponential growing ranges.
+            while (pos < end)
+            {
+                size_t bytes_to_copy = std::min(pos - begin, end - pos);
+                memcpy(pos, begin, bytes_to_copy);
+                pos += bytes_to_copy;
+            }
+        }
 
-            for (size_t i = 0; i < vec.size(); ++i)
+        auto begin = reinterpret_cast<char *>(dst_data.data());
+        auto pos = begin;
+
+        for (size_t i = 0; i < vec.size(); ++i)
+        {
+            if constexpr (std::is_same_v<DataType, DataTypeDateTime64>)
+            {
+                for (auto & instruction : instructions)
+                {
+                    // since right now LUT does not support Int64-values and not format instructions for subsecond parts,
+                    // treat DatTime64 values just as DateTime values by ignoring fractional and casting to UInt32.
+                    const auto c = DecimalUtils::split(vec[i], scale);
+                    instruction.perform(pos, static_cast<UInt32>(c.whole), time_zone);
+                }
+            }
+            else
             {
                 for (auto & instruction : instructions)
                     instruction.perform(pos, vec[i], time_zone);
-
-                dst_offsets[i] = pos - begin;
             }
 
-            dst_data.resize(pos - begin);
-            block.getByPosition(result).column = std::move(col_res);
-            return true;
+            dst_offsets[i] = pos - begin;
         }
 
-        return false;
+        dst_data.resize(pos - begin);
+        block.getByPosition(result).column = std::move(col_res);
+        return true;
     }
 
     template <typename T>

dbms/src/Functions/now.cpp

@@ -1,9 +1,12 @@
 #include <DataTypes/DataTypeDateTime.h>
 
+#include <Core/DecimalFunctions.h>
 #include <Functions/IFunction.h>
 #include <Functions/FunctionFactory.h>
 #include <Core/Field.h>
 
+#include <time.h>
+
 
 namespace DB
 

dbms/src/Functions/now64.cpp

@@ -0,0 +1,98 @@
+#include <DataTypes/DataTypeDateTime64.h>
+
+#include <Core/DecimalFunctions.h>
+#include <Functions/IFunction.h>
+#include <Functions/FunctionFactory.h>
+
+#include <Common/assert_cast.h>
+
+#include <time.h>
+
+
+namespace DB
+{
+
+namespace ErrorCodes
+{
+    extern const int ILLEGAL_COLUMN;
+    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
+}
+
+DateTime64::NativeType nowSubsecond(UInt32 scale)
+{
+    const Int32 fractional_scale = 9;
+    timespec spec;
+    clock_gettime(CLOCK_REALTIME, &spec);
+
+    DecimalUtils::DecimalComponents<DateTime64::NativeType> components{spec.tv_sec, spec.tv_nsec};
+
+    // clock_gettime produces subsecond part in nanoseconds, but decimalFromComponents fractional is scale-dependent.
+    // Andjust fractional to scale, e.g. for 123456789 nanoseconds:
+    //   if scale is  6 (miscoseconds) => divide by 9 - 6 = 3 to get 123456 microseconds
+    //   if scale is 12 (picoseconds)  => multiply by abs(9 - 12) = 3 to get 123456789000 picoseconds
+    const auto adjust_scale = fractional_scale - static_cast<Int32>(scale);
+    if (adjust_scale < 0)
+        components.fractional *= intExp10(std::abs(adjust_scale));
+    else if (adjust_scale > 0)
+        components.fractional /= intExp10(adjust_scale);
+
+    return DecimalUtils::decimalFromComponents<DateTime64>(components, scale).value;
+}
+
+class FunctionNow64 : public IFunction
+{
+public:
+    static constexpr auto name = "now64";
+    static FunctionPtr create(const Context &) { return std::make_shared<FunctionNow64>(); }
+
+    String getName() const override
+    {
+        return name;
+    }
+
+    bool isVariadic() const override { return true; }
+    size_t getNumberOfArguments() const override { return 0; }
+    ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return ColumnNumbers{0}; }
+    bool isDeterministic() const override { return false; }
+
+    // Return type depends on argument value.
+    DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
+    {
+        UInt32 scale = DataTypeDateTime64::default_scale;
+
+        // Type check is similar to the validateArgumentType, trying to keep error codes and messages as close to the said function as possible.
+        if (arguments.size() >= 1)
+        {
+            const auto & argument = arguments[0];
+            if (!isInteger(argument.type) || !isColumnConst(*argument.column))
+                throw Exception("Illegal type " + argument.type->getName() +
+                                " of 0" +
+                                " argument of function " + getName() +
+                                ". Expected const integer.",
+                                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
+
+            scale = argument.column->get64(0);
+        }
+
+        return std::make_shared<DataTypeDateTime64>(scale);
+    }
+
+    void executeImpl(Block & block, const ColumnNumbers & /*arguments*/, size_t result, size_t input_rows_count) override
+    {
+        auto & result_col = block.getByPosition(result);
+        UInt32 scale = DataTypeDateTime64::default_scale;
+        if (const auto * dt64 = assert_cast<const DataTypeDateTime64 *>(result_col.type.get()))
+        {
+            scale = dt64->getScale();
+        }
+
+        result_col.column = DataTypeDateTime64(scale).createColumnConst(input_rows_count, nowSubsecond(scale));
+    }
+};
+
+void registerFunctionNow64(FunctionFactory & factory)
+{
+    factory.registerFunction<FunctionNow64>(FunctionFactory::CaseInsensitive);
+}
+
+}

dbms/src/Functions/registerFunctionsDateTime.cpp

@@ -37,6 +37,7 @@ void registerFunctionToRelativeMinuteNum(FunctionFactory &);
 void registerFunctionToRelativeSecondNum(FunctionFactory &);
 void registerFunctionToTime(FunctionFactory &);
 void registerFunctionNow(FunctionFactory &);
+void registerFunctionNow64(FunctionFactory &);
 void registerFunctionToday(FunctionFactory &);
 void registerFunctionYesterday(FunctionFactory &);
 void registerFunctionTimeSlot(FunctionFactory &);
@@ -101,6 +102,7 @@ void registerFunctionsDateTime(FunctionFactory & factory)
     registerFunctionToRelativeSecondNum(factory);
     registerFunctionToTime(factory);
     registerFunctionNow(factory);
+    registerFunctionNow64(factory);
     registerFunctionToday(factory);
     registerFunctionYesterday(factory);
     registerFunctionTimeSlot(factory);

dbms/src/Functions/runningDifference.h

@@ -5,6 +5,7 @@
 #include <Common/assert_cast.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypesNumber.h>
 #include <DataTypes/NumberTraits.h>
 #include <DataTypes/DataTypeNullable.h>

dbms/src/Functions/timeSlots.cpp

@@ -1,5 +1,6 @@
-#include <DataTypes/DataTypeDateTime.h>
 #include <DataTypes/DataTypeArray.h>
+#include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <Columns/ColumnArray.h>
 #include <Columns/ColumnsNumber.h>
 

dbms/src/Functions/toStartOfInterval.cpp

@@ -1,6 +1,8 @@
+#include <common/DateLUTImpl.h>
 #include <Columns/ColumnsNumber.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypeInterval.h>
 #include <Functions/DateTimeTransforms.h>
 #include <Functions/FunctionFactory.h>
@@ -125,7 +127,6 @@ namespace
             return time_zone.toStartOfSecondInterval(t, seconds);
         }
     };
-
 }
 
 
@@ -233,26 +234,34 @@ private:
     ColumnPtr dispatchForColumns(
         const ColumnWithTypeAndName & time_column, const ColumnWithTypeAndName & interval_column, const DateLUTImpl & time_zone)
     {
-        if (WhichDataType(time_column.type.get()).isDateTime())
+        const auto & from_datatype = *time_column.type.get();
+        const auto which_type = WhichDataType(from_datatype);
+        if (which_type.isDateTime())
         {
             const auto * time_column_vec = checkAndGetColumn<ColumnUInt32>(time_column.column.get());
             if (time_column_vec)
-                return dispatchForIntervalColumn(*time_column_vec, interval_column, time_zone);
+                return dispatchForIntervalColumn(assert_cast<const DataTypeDateTime&>(from_datatype), *time_column_vec, interval_column, time_zone);
         }
-        if (WhichDataType(time_column.type.get()).isDate())
+        if (which_type.isDate())
         {
             const auto * time_column_vec = checkAndGetColumn<ColumnUInt16>(time_column.column.get());
             if (time_column_vec)
-                return dispatchForIntervalColumn(*time_column_vec, interval_column, time_zone);
+                return dispatchForIntervalColumn(assert_cast<const DataTypeDate&>(from_datatype), *time_column_vec, interval_column, time_zone);
+        }
+        if (which_type.isDateTime64())
+        {
+            const auto * time_column_vec = checkAndGetColumn<DataTypeDateTime64::ColumnType>(time_column.column.get());
+            if (time_column_vec)
+                return dispatchForIntervalColumn(assert_cast<const DataTypeDateTime64&>(from_datatype), *time_column_vec, interval_column, time_zone);
         }
         throw Exception(
             "Illegal column for first argument of function " + getName() + ". Must contain dates or dates with time",
             ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
     }
 
-    template <typename FromType>
+    template <typename ColumnType, typename FromDataType>
     ColumnPtr dispatchForIntervalColumn(
-        const ColumnVector<FromType> & time_column, const ColumnWithTypeAndName & interval_column, const DateLUTImpl & time_zone)
+        const FromDataType & from, const ColumnType & time_column, const ColumnWithTypeAndName & interval_column, const DateLUTImpl & time_zone)
     {
         const auto * interval_type = checkAndGetDataType<DataTypeInterval>(interval_column.type.get());
         if (!interval_type)
@@ -270,36 +279,47 @@ private:
         switch (interval_type->getKind())
         {
             case IntervalKind::Second:
-                return execute<FromType, UInt32, IntervalKind::Second>(time_column, num_units, time_zone);
+                return execute<FromDataType, UInt32, IntervalKind::Second>(from, time_column, num_units, time_zone);
             case IntervalKind::Minute:
-                return execute<FromType, UInt32, IntervalKind::Minute>(time_column, num_units, time_zone);
+                return execute<FromDataType, UInt32, IntervalKind::Minute>(from, time_column, num_units, time_zone);
             case IntervalKind::Hour:
-                return execute<FromType, UInt32, IntervalKind::Hour>(time_column, num_units, time_zone);
+                return execute<FromDataType, UInt32, IntervalKind::Hour>(from, time_column, num_units, time_zone);
             case IntervalKind::Day:
-                return execute<FromType, UInt32, IntervalKind::Day>(time_column, num_units, time_zone);
+                return execute<FromDataType, UInt32, IntervalKind::Day>(from, time_column, num_units, time_zone);
             case IntervalKind::Week:
-                return execute<FromType, UInt16, IntervalKind::Week>(time_column, num_units, time_zone);
+                return execute<FromDataType, UInt16, IntervalKind::Week>(from, time_column, num_units, time_zone);
             case IntervalKind::Month:
-                return execute<FromType, UInt16, IntervalKind::Month>(time_column, num_units, time_zone);
+                return execute<FromDataType, UInt16, IntervalKind::Month>(from, time_column, num_units, time_zone);
             case IntervalKind::Quarter:
-                return execute<FromType, UInt16, IntervalKind::Quarter>(time_column, num_units, time_zone);
+                return execute<FromDataType, UInt16, IntervalKind::Quarter>(from, time_column, num_units, time_zone);
             case IntervalKind::Year:
-                return execute<FromType, UInt16, IntervalKind::Year>(time_column, num_units, time_zone);
+                return execute<FromDataType, UInt16, IntervalKind::Year>(from, time_column, num_units, time_zone);
         }
 
         __builtin_unreachable();
     }
 
-    template <typename FromType, typename ToType, IntervalKind::Kind unit>
-    ColumnPtr execute(const ColumnVector<FromType> & time_column, UInt64 num_units, const DateLUTImpl & time_zone)
+
+    template <typename FromDataType, typename ToType, IntervalKind::Kind unit, typename ColumnType>
+    ColumnPtr execute(const FromDataType & from_datatype, const ColumnType & time_column, UInt64 num_units, const DateLUTImpl & time_zone)
     {
         const auto & time_data = time_column.getData();
         size_t size = time_column.size();
         auto result = ColumnVector<ToType>::create();
         auto & result_data = result->getData();
         result_data.resize(size);
-        for (size_t i = 0; i != size; ++i)
-            result_data[i] = Transform<unit>::execute(time_data[i], num_units, time_zone);
+
+        if constexpr (std::is_same_v<FromDataType, DataTypeDateTime64>)
+        {
+            const auto transform = DateTime64BasicTransformWrapper<Transform<unit>>{from_datatype.getScale()};
+            for (size_t i = 0; i != size; ++i)
+                result_data[i] = transform.execute(time_data[i], num_units, time_zone);
+        }
+        else
+        {
+            for (size_t i = 0; i != size; ++i)
+                result_data[i] = Transform<unit>::execute(time_data[i], num_units, time_zone);
+        }
         return result;
     }
 };

dbms/src/Functions/toTimeZone.cpp

@@ -1,4 +1,5 @@
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 
 #include <Core/Field.h>
 
@@ -7,6 +8,7 @@
 #include <Functions/extractTimeZoneFromFunctionArguments.h>
 
 #include <IO/WriteHelpers.h>
+#include <Common/assert_cast.h>
 
 
 namespace DB
@@ -39,12 +41,17 @@ public:
                 + toString(arguments.size()) + ", should be 2",
                 ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
 
-        if (!WhichDataType(arguments[0].type).isDateTime())
+        const auto which_type = WhichDataType(arguments[0].type);
+        if (!which_type.isDateTime() && !which_type.isDateTime64())
             throw Exception{"Illegal type " + arguments[0].type->getName() + " of argument of function " + getName() +
-                ". Should be DateTime", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
+                ". Should be DateTime or DateTime64", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
 
         String time_zone_name = extractTimeZoneNameFromFunctionArguments(arguments, 1, 0);
-        return std::make_shared<DataTypeDateTime>(time_zone_name);
+        if (which_type.isDateTime())
+            return std::make_shared<DataTypeDateTime>(time_zone_name);
+
+        const auto * date_time64 = assert_cast<const DataTypeDateTime64 *>(arguments[0].type.get());
+        return std::make_shared<DataTypeDateTime64>(date_time64->getScale(), time_zone_name);
     }
 
     void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override

dbms/src/IO/ReadHelpers.h

@@ -12,14 +12,17 @@
 #include <common/LocalDate.h>
 #include <common/LocalDateTime.h>
 #include <common/StringRef.h>
+#include <common/arithmeticOverflow.h>
 
 #include <Core/Types.h>
+#include <Core/DecimalFunctions.h>
 #include <Core/UUID.h>
 
 #include <Common/Exception.h>
 #include <Common/StringUtils/StringUtils.h>
 #include <Common/Arena.h>
 #include <Common/UInt128.h>
+#include <Common/intExp.h>
 
 #include <Formats/FormatSettings.h>
 
@@ -29,6 +32,8 @@
 #include <IO/VarInt.h>
 #include <IO/ZlibInflatingReadBuffer.h>
 
+#include <DataTypes/DataTypeDateTime.h>
+
 #ifdef __clang__
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdouble-promotion"
@@ -252,7 +257,13 @@ inline void readBoolTextWord(bool & x, ReadBuffer & buf)
     }
 }
 
-template <typename T, typename ReturnType = void>
+enum class ReadIntTextCheckOverflow
+{
+    DO_NOT_CHECK_OVERFLOW,
+    CHECK_OVERFLOW,
+};
+
+template <typename T, typename ReturnType = void, ReadIntTextCheckOverflow check_overflow = ReadIntTextCheckOverflow::DO_NOT_CHECK_OVERFLOW>
 ReturnType readIntTextImpl(T & x, ReadBuffer & buf)
 {
     static constexpr bool throw_exception = std::is_same_v<ReturnType, void>;
@@ -267,6 +278,7 @@ ReturnType readIntTextImpl(T & x, ReadBuffer & buf)
             return ReturnType(false);
     }
 
+    const size_t initial_pos = buf.count();
     while (!buf.eof())
     {
         switch (*buf.position())
@@ -274,7 +286,7 @@ ReturnType readIntTextImpl(T & x, ReadBuffer & buf)
             case '+':
                 break;
             case '-':
-                if (is_signed_v<T>)
+                if constexpr (is_signed_v<T>)
                     negative = true;
                 else
                 {
@@ -294,30 +306,48 @@ ReturnType readIntTextImpl(T & x, ReadBuffer & buf)
             case '7': [[fallthrough]];
             case '8': [[fallthrough]];
             case '9':
+                if constexpr (check_overflow == ReadIntTextCheckOverflow::CHECK_OVERFLOW)
+                {
+                    // perform relativelly slow overflow check only when number of decimal digits so far is close to the max for given type.
+                    if (buf.count() - initial_pos >= std::numeric_limits<T>::max_digits10)
+                    {
+                        if (common::mulOverflow(res, static_cast<decltype(res)>(10), res)
+                            || common::addOverflow(res, static_cast<decltype(res)>(*buf.position() - '0'), res))
+                            return ReturnType(false);
+                        break;
+                    }
+                }
                 res *= 10;
                 res += *buf.position() - '0';
                 break;
             default:
-                x = negative ? -res : res;
-                return ReturnType(true);
+                goto end;
         }
         ++buf.position();
     }
 
+end:
     x = negative ? -res : res;
+
     return ReturnType(true);
 }
 
-template <typename T>
+template <ReadIntTextCheckOverflow check_overflow = ReadIntTextCheckOverflow::DO_NOT_CHECK_OVERFLOW, typename T>
 void readIntText(T & x, ReadBuffer & buf)
 {
-    readIntTextImpl<T, void>(x, buf);
+    readIntTextImpl<T, void, check_overflow>(x, buf);
 }
 
-template <typename T>
+template <ReadIntTextCheckOverflow check_overflow = ReadIntTextCheckOverflow::CHECK_OVERFLOW, typename T>
 bool tryReadIntText(T & x, ReadBuffer & buf)
 {
-    return readIntTextImpl<T, bool>(x, buf);
+    return readIntTextImpl<T, bool, check_overflow>(x, buf);
+}
+
+template <ReadIntTextCheckOverflow check_overflow = ReadIntTextCheckOverflow::DO_NOT_CHECK_OVERFLOW, typename T>
+void readIntText(Decimal<T> & x, ReadBuffer & buf)
+{
+    readIntText<check_overflow>(x.value, buf);
 }
 
 /** More efficient variant (about 1.5 times on real dataset).
@@ -617,22 +647,74 @@ inline ReturnType readDateTimeTextImpl(time_t & datetime, ReadBuffer & buf, cons
         }
         else
             /// Why not readIntTextUnsafe? Because for needs of AdFox, parsing of unix timestamp with leading zeros is supported: 000...NNNN.
-            return readIntTextImpl<time_t, ReturnType>(datetime, buf);
+            return readIntTextImpl<time_t, ReturnType, ReadIntTextCheckOverflow::CHECK_OVERFLOW>(datetime, buf);
     }
     else
         return readDateTimeTextFallback<ReturnType>(datetime, buf, date_lut);
 }
 
+template <typename ReturnType>
+inline ReturnType readDateTimeTextImpl(DateTime64 & datetime64, UInt32 scale, ReadBuffer & buf, const DateLUTImpl & date_lut)
+{
+    time_t whole;
+    if (!readDateTimeTextImpl<bool>(whole, buf, date_lut))
+    {
+        return ReturnType(false);
+    }
+
+    DB::DecimalUtils::DecimalComponents<DateTime64::NativeType> c{static_cast<DateTime64::NativeType>(whole), 0};
+
+    if (!buf.eof() && *buf.position() == '.')
+    {
+        buf.ignore(1); // skip separator
+        const auto pos_before_fractional = buf.count();
+        if (!tryReadIntText<ReadIntTextCheckOverflow::CHECK_OVERFLOW>(c.fractional, buf))
+        {
+            return ReturnType(false);
+        }
+
+        // Adjust fractional part to the scale, since decimalFromComponents knows nothing
+        // about convention of ommiting trailing zero on fractional part
+        // and assumes that fractional part value is less than 10^scale.
+
+        // If scale is 3, but we read '12', promote fractional part to '120'.
+        // And vice versa: if we read '1234', denote it to '123'.
+        const auto fractional_length = static_cast<Int32>(buf.count() - pos_before_fractional);
+        if (const auto adjust_scale = static_cast<Int32>(scale) - fractional_length; adjust_scale > 0)
+        {
+            c.fractional *= common::exp10_i64(adjust_scale);
+        }
+        else if (adjust_scale < 0)
+        {
+            c.fractional /= common::exp10_i64(-1 * adjust_scale);
+        }
+    }
+
+    datetime64 = DecimalUtils::decimalFromComponents<DateTime64>(c, scale);
+
+    return ReturnType(true);
+}
+
 inline void readDateTimeText(time_t & datetime, ReadBuffer & buf, const DateLUTImpl & date_lut = DateLUT::instance())
 {
     readDateTimeTextImpl<void>(datetime, buf, date_lut);
 }
 
+inline void readDateTime64Text(DateTime64 & datetime64, UInt32 scale, ReadBuffer & buf, const DateLUTImpl & date_lut = DateLUT::instance())
+{
+    readDateTimeTextImpl<void>(datetime64, scale, buf, date_lut);
+}
+
 inline bool tryReadDateTimeText(time_t & datetime, ReadBuffer & buf, const DateLUTImpl & date_lut = DateLUT::instance())
 {
     return readDateTimeTextImpl<bool>(datetime, buf, date_lut);
 }
 
+inline bool tryReadDateTime64Text(DateTime64 & datetime64, UInt32 scale, ReadBuffer & buf, const DateLUTImpl & date_lut = DateLUT::instance())
+{
+    return readDateTimeTextImpl<bool>(datetime64, scale, buf, date_lut);
+}
+
 inline void readDateTimeText(LocalDateTime & datetime, ReadBuffer & buf)
 {
     char s[19];
@@ -858,11 +940,11 @@ void readAndThrowException(ReadBuffer & buf, const String & additional_message =
 
 /** Helper function for implementation.
   */
-template <typename T>
+template <ReadIntTextCheckOverflow check_overflow = ReadIntTextCheckOverflow::CHECK_OVERFLOW, typename T>
 static inline const char * tryReadIntText(T & x, const char * pos, const char * end)
 {
     ReadBufferFromMemory in(pos, end - pos);
-    tryReadIntText(x, in);
+    tryReadIntText<check_overflow>(x, in);
     return pos + in.count();
 }
 

dbms/src/IO/WriteHelpers.h

@@ -12,6 +12,7 @@
 #include <common/find_symbols.h>
 #include <common/StringRef.h>
 
+#include <Core/DecimalFunctions.h>
 #include <Core/Types.h>
 #include <Core/UUID.h>
 
@@ -29,7 +30,6 @@
 
 #include <Formats/FormatSettings.h>
 
-
 namespace DB
 {
 
@@ -694,6 +694,46 @@ inline void writeDateTimeText(time_t datetime, WriteBuffer & buf, const DateLUTI
             date_lut.toHour(datetime), date_lut.toMinute(datetime), date_lut.toSecond(datetime)), buf);
 }
 
+/// In the format YYYY-MM-DD HH:MM:SS.NNNNNNNNN, according to the specified time zone.
+template <char date_delimeter = '-', char time_delimeter = ':', char between_date_time_delimiter = ' ', char fractional_time_delimiter = '.'>
+inline void writeDateTimeText(DateTime64 datetime64, UInt32 scale, WriteBuffer & buf, const DateLUTImpl & date_lut = DateLUT::instance())
+{
+    static constexpr UInt32 MaxScale = DecimalUtils::maxPrecision<DateTime64>();
+    scale = scale > MaxScale ? MaxScale : scale;
+    if (unlikely(!datetime64))
+    {
+        static const char s[] =
+        {
+            '0', '0', '0', '0', date_delimeter, '0', '0', date_delimeter, '0', '0',
+            between_date_time_delimiter,
+            '0', '0', time_delimeter, '0', '0', time_delimeter, '0', '0',
+            fractional_time_delimiter,
+            // Exactly MaxScale zeroes
+            '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0'
+        };
+        buf.write(s, sizeof(s) - (MaxScale - scale));
+        return;
+    }
+    auto c = DecimalUtils::split(datetime64, scale);
+    const auto & values = date_lut.getValues(c.whole);
+    writeDateTimeText<date_delimeter, time_delimeter, between_date_time_delimiter>(
+        LocalDateTime(values.year, values.month, values.day_of_month,
+            date_lut.toHour(c.whole), date_lut.toMinute(c.whole), date_lut.toSecond(c.whole)), buf);
+
+    if (scale > 0)
+    {
+        buf.write(fractional_time_delimiter);
+
+        char data[20] = {'0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0'};
+        static_assert(sizeof(data) >= MaxScale);
+
+        auto fractional = c.fractional;
+        for (Int32 pos = scale - 1; pos >= 0 && fractional; --pos, fractional /= DateTime64(10))
+            data[pos] += fractional % DateTime64(10);
+
+        writeString(&data[0], static_cast<size_t>(scale), buf);
+    }
+}
 
 /// In the RFC 1123 format: "Tue, 03 Dec 2019 00:11:50 GMT". You must provide GMT DateLUT.
 /// This is needed for HTTP requests.
@@ -772,9 +812,7 @@ void writeText(Decimal<T> value, UInt32 scale, WriteBuffer & ostr)
         writeChar('-', ostr); /// avoid crop leading minus when whole part is zero
     }
 
-    T whole_part = value;
-    if (scale)
-        whole_part = value / Decimal<T>::getScaleMultiplier(scale);
+    const T whole_part = DecimalUtils::getWholePart(value, scale);
 
     writeIntText(whole_part, ostr);
     if (scale)

dbms/src/IO/parseDateTimeBestEffort.cpp

@@ -6,6 +6,7 @@
 #include <IO/WriteHelpers.h>
 #include <IO/parseDateTimeBestEffort.h>
 
+#include <limits>
 
 namespace DB
 {
@@ -64,9 +65,32 @@ inline void readDecimalNumber(T & res, const char * src)
     readDecimalNumberImpl<num_digits - 1, 1>(res, src);
 }
 
+template <typename T>
+inline void readDecimalNumber(T & res, size_t num_digits, const char * src)
+{
+#define READ_DECIMAL_NUMBER(N)         res *= common::exp10_i32(N); readDecimalNumber<N>(res, src); src += N; num_digits -= N; break
+
+    while (num_digits)
+    {
+        switch (num_digits)
+        {
+            case 3: READ_DECIMAL_NUMBER(3); break;
+            case 2: READ_DECIMAL_NUMBER(2); break;
+            case 1: READ_DECIMAL_NUMBER(1); break;
+            default: READ_DECIMAL_NUMBER(4);
+        }
+    }
+#undef DECIMAL_NUMBER_CASE
+}
+
+struct DateTimeSubsecondPart
+{
+    Int64 value;
+    UInt8 digits;
+};
 
 template <typename ReturnType>
-ReturnType parseDateTimeBestEffortImpl(time_t & res, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
+ReturnType parseDateTimeBestEffortImpl(time_t & res, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone, DateTimeSubsecondPart * fractional = nullptr)
 {
     auto on_error = [](const std::string & message [[maybe_unused]], int code [[maybe_unused]])
     {
@@ -113,7 +137,7 @@ ReturnType parseDateTimeBestEffortImpl(time_t & res, ReadBuffer & in, const Date
 
     while (!in.eof())
     {
-        char digits[14];
+        char digits[std::numeric_limits<UInt64>::digits10];
 
         size_t num_digits = 0;
 
@@ -358,9 +382,18 @@ ReturnType parseDateTimeBestEffortImpl(time_t & res, ReadBuffer & in, const Date
                     return on_error("Cannot read DateTime: unexpected point symbol", ErrorCodes::CANNOT_PARSE_DATETIME);
 
                 ++in.position();
+                num_digits = readDigits(digits, sizeof(digits), in);
+                if (fractional)
+                {
+                    using FractionalType = typename std::decay<decltype(fractional->value)>::type;
+                    // Reading more decimal digits than fits into FractionalType would case an
+                    // overflow, so it is better to skip all digits from the right side that do not
+                    // fit into result type. To provide less precise value rather than bogus one.
+                    num_digits = std::min(static_cast<size_t>(std::numeric_limits<FractionalType>::digits10), num_digits);
 
-                /// Just ignore fractional part of second.
-                readDigits(digits, sizeof(digits), in);
+                    fractional->digits = num_digits;
+                    readDecimalNumber(fractional->value, num_digits, digits);
+                }
             }
             else if (c == '+' || c == '-')
             {
@@ -517,6 +550,28 @@ ReturnType parseDateTimeBestEffortImpl(time_t & res, ReadBuffer & in, const Date
     return ReturnType(true);
 }
 
+template <typename ReturnType>
+ReturnType parseDateTime64BestEffortImpl(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
+{
+    time_t whole;
+    DateTimeSubsecondPart subsecond = {0, 0}; // needs to be explicitly initialized sine it could be missing from input string
+    if (!parseDateTimeBestEffortImpl<bool>(whole, in, local_time_zone, utc_time_zone, &subsecond))
+        return ReturnType(false);
+
+    DateTime64::NativeType fractional = subsecond.value;
+    if (scale < subsecond.digits)
+    {
+        fractional /= common::exp10_i64(subsecond.digits - scale);
+    }
+    else if (scale > subsecond.digits)
+    {
+        fractional *= common::exp10_i64(scale - subsecond.digits);
+    }
+
+    res = DecimalUtils::decimalFromComponents<DateTime64>(whole, fractional, scale);
+    return ReturnType(true);
+}
+
 }
 
 #if defined(__PPC__)
@@ -535,4 +590,14 @@ bool tryParseDateTimeBestEffort(time_t & res, ReadBuffer & in, const DateLUTImpl
     return parseDateTimeBestEffortImpl<bool>(res, in, local_time_zone, utc_time_zone);
 }
 
+void parseDateTime64BestEffort(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
+{
+    return parseDateTime64BestEffortImpl<void>(res, scale, in, local_time_zone, utc_time_zone);
+}
+
+bool tryParseDateTime64BestEffort(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
+{
+    return parseDateTime64BestEffortImpl<bool>(res, scale, in, local_time_zone, utc_time_zone);
+}
+
 }

dbms/src/IO/parseDateTimeBestEffort.h

@@ -1,6 +1,8 @@
 #include <stddef.h>
 #include <time.h>
 
+#include <Core/Types.h>
+
 class DateLUTImpl;
 
 namespace DB
@@ -55,5 +57,7 @@ class ReadBuffer;
 
 void parseDateTimeBestEffort(time_t & res, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone);
 bool tryParseDateTimeBestEffort(time_t & res, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone);
+void parseDateTime64BestEffort(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone);
+bool tryParseDateTime64BestEffort(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone);
 
 }

dbms/src/IO/tests/gtest_DateTime64_parsing_and_writing.cpp

@@ -0,0 +1,185 @@
+#include <gtest/gtest.h>
+
+#include <IO/ReadHelpers.h>
+#include <IO/WriteHelpers.h>
+#include <IO/parseDateTimeBestEffort.h>
+
+#include <Common/PODArray.h>
+
+/** Test formatting and parsing predefined DateTime64 values to/from string
+ */
+
+using namespace DB;
+
+struct DateTime64StringsTestParam
+{
+    const std::string_view comment;
+    const std::string_view string;
+    DateTime64 dt64;
+    UInt32 scale;
+    const DateLUTImpl & timezone = DateLUT::instance();
+};
+
+std::ostream & operator << (std::ostream & ostr, const DateTime64StringsTestParam & param)
+{
+    return ostr << param.comment;
+}
+
+class DateTime64StringsTest : public ::testing::TestWithParam<DateTime64StringsTestParam> {};
+class DateTime64StringParseTest : public DateTime64StringsTest{};
+class DateTime64StringParseBestEffortTest : public DateTime64StringsTest{};
+class DateTime64StringWriteTest : public DateTime64StringsTest {};
+
+
+TEST_P(DateTime64StringParseTest, readDateTime64Text)
+{
+    const auto & param = GetParam();
+    ReadBufferFromMemory read_buffer(param.string.data(), param.string.size());
+
+    DateTime64 actual;
+    EXPECT_TRUE(tryReadDateTime64Text(actual, param.scale, read_buffer));
+
+    EXPECT_EQ(param.dt64, actual);
+}
+
+TEST_P(DateTime64StringParseTest, parseDateTime64BestEffort)
+{
+    const auto & param = GetParam();
+    ReadBufferFromMemory read_buffer(param.string.data(), param.string.size());
+
+    DateTime64 actual;
+    EXPECT_TRUE(tryParseDateTime64BestEffort(actual, param.scale, read_buffer, param.timezone, DateLUT::instance("UTC")));
+
+    EXPECT_EQ(param.dt64, actual);
+}
+
+TEST_P(DateTime64StringWriteTest, WriteText)
+{
+    const auto & param = GetParam();
+
+    PaddedPODArray<char> actual_string(param.string.size() * 2, '\0'); // TODO: detect overflows
+
+    WriteBuffer write_buffer(actual_string.data(), actual_string.size());
+    EXPECT_NO_THROW(writeDateTimeText(param.dt64, param.scale, write_buffer));
+
+    EXPECT_STREQ(param.string.data(), actual_string.data());
+}
+
+TEST_P(DateTime64StringParseBestEffortTest, parse)
+{
+    const auto & param = GetParam();
+    ReadBufferFromMemory read_buffer(param.string.data(), param.string.size());
+
+    DateTime64 actual;
+    EXPECT_TRUE(tryParseDateTime64BestEffort(actual, param.scale, read_buffer, param.timezone, DateLUT::instance("UTC")));
+
+    EXPECT_EQ(param.dt64, actual);
+}
+
+
+// YYYY-MM-DD HH:MM:SS.NNNNNNNNN
+INSTANTIATE_TEST_CASE_P(Basic,
+    DateTime64StringParseTest,
+    ::testing::ValuesIn(std::initializer_list<DateTime64StringsTestParam>{
+        {
+            "When subsecond part is missing from string it is set to zero.",
+            "2019-09-16 19:20:17",
+            1568650817'000,
+            3
+        },
+        {
+            "When subsecond part is present in string, but it is zero, it is set to zero.",
+            "2019-09-16 19:20:17.0",
+            1568650817'000,
+            3
+        },
+        {
+            "When scale is 0, subsecond part is not set.",
+            "2019-09-16 19:20:17",
+            1568650817ULL,
+            0
+        },
+        {
+            "When scale is 0, subsecond part is 0 despite beeing present in string.",
+            "2019-09-16 19:20:17.123",
+            1568650817ULL,
+            0
+        },
+        {
+            "When subsecond part is present in string, it is set correctly to DateTime64 value of scale 3.",
+            "2019-09-16 19:20:17.123",
+            1568650817'123,
+            3
+        },
+        {
+            "When subsecond part is present in string (and begins with 0), it is set correctly to DateTime64 value of scale 3.",
+            "2019-09-16 19:20:17.012",
+            1568650817'012,
+            3
+        },
+        {
+            "When subsecond part scale is smaller than DateTime64 scale, subsecond part is properly adjusted (as if padded from right with zeroes).",
+            "2019-09-16 19:20:17.123",
+            1568650817'12300ULL,
+            5
+        },
+        {
+            "When subsecond part scale is larger than DateTime64 scale, subsecond part is truncated.",
+            "2019-09-16 19:20:17.123",
+            1568650817'1ULL,
+            1
+        }
+    }),
+);
+
+INSTANTIATE_TEST_CASE_P(BestEffort,
+    DateTime64StringParseBestEffortTest,
+    ::testing::ValuesIn(std::initializer_list<DateTime64StringsTestParam>{
+        {
+            "When subsecond part is unreasonably large, it fals to parse",
+            "2019-09-16 19:20:17.12345678910111213141516171819202122233435363738393031323334353637383940414243444546474849505152535455565758596061626364",
+            1568650817'123456ULL,
+            6
+        }
+    }),
+);
+
+
+// TODO: add negative test cases for invalid strings, verifying that error is reported properly
+
+INSTANTIATE_TEST_CASE_P(Basic,
+    DateTime64StringWriteTest,
+    ::testing::ValuesIn(std::initializer_list<DateTime64StringsTestParam>{
+        {
+            "non-zero subsecond part on DateTime64 with scale of 3",
+            "2019-09-16 19:20:17.123",
+            1568650817'123,
+            3
+        },
+        {
+            "non-zero subsecond part on DateTime64 with scale of 5",
+            "2019-09-16 19:20:17.12345",
+            1568650817'12345ULL,
+            5
+        },
+        {
+            "Zero subsecond part is written to string",
+            "2019-09-16 19:20:17.000",
+            1568650817'000ULL,
+            3
+        },
+        {
+            "When scale is 0, subsecond part (and separtor) is missing from string",
+            "2019-09-16 19:20:17",
+            1568650817ULL,
+            0
+        },
+        {
+            "Subsecond part with leading zeroes is written to string correctly",
+            "2019-09-16 19:20:17.001",
+            1568650817'001ULL,
+            3
+        }
+    }),
+);
+

dbms/src/Interpreters/Context.cpp

@@ -1508,7 +1508,18 @@ BackgroundProcessingPool & Context::getBackgroundMovePool()
 {
     auto lock = getLock();
     if (!shared->background_move_pool)
-        shared->background_move_pool.emplace(settings.background_move_pool_size, "BackgroundMovePool", "BgMoveProcPool");
+    {
+        BackgroundProcessingPool::PoolSettings pool_settings;
+        auto & config = getConfigRef();
+        pool_settings.thread_sleep_seconds = config.getDouble("background_move_processing_pool_thread_sleep_seconds", 10);
+        pool_settings.thread_sleep_seconds_random_part = config.getDouble("background_move_processing_pool_thread_sleep_seconds_random_part", 1.0);
+        pool_settings.thread_sleep_seconds_if_nothing_to_do = config.getDouble("background_move_processing_pool_thread_sleep_seconds_if_nothing_to_do", 0.1);
+        pool_settings.task_sleep_seconds_when_no_work_min = config.getDouble("background_move_processing_pool_task_sleep_seconds_when_no_work_min", 10);
+        pool_settings.task_sleep_seconds_when_no_work_max = config.getDouble("background_move_processing_pool_task_sleep_seconds_when_no_work_max", 600);
+        pool_settings.task_sleep_seconds_when_no_work_multiplier = config.getDouble("background_move_processing_pool_task_sleep_seconds_when_no_work_multiplier", 1.1);
+        pool_settings.task_sleep_seconds_when_no_work_random_part = config.getDouble("background_move_processing_pool_task_sleep_seconds_when_no_work_random_part", 1.0);
+        shared->background_move_pool.emplace(settings.background_move_pool_size, pool_settings, "BackgroundMovePool", "BgMoveProcPool");
+    }
     return *shared->background_move_pool;
 }
 

dbms/src/Interpreters/Join.cpp

@@ -333,7 +333,7 @@ void Join::setSampleBlock(const Block & block)
         asof_type = AsofRowRefs::getTypeSize(asof_column, asof_size);
         if (!asof_type)
         {
-            std::string msg = "ASOF join not supported for type";
+            std::string msg = "ASOF join not supported for type: ";
             msg += asof_column->getFamilyName();
             throw Exception(msg, ErrorCodes::BAD_TYPE_OF_FIELD);
         }

dbms/src/Interpreters/RowRefs.cpp

@@ -1,9 +1,12 @@
 #include <Interpreters/RowRefs.h>
 
+#include <Core/Block.h>
+#include <Core/Types.h>
 #include <Common/typeid_cast.h>
 #include <Common/ColumnsHashing.h>
-#include <Core/Block.h>
 #include <Columns/IColumn.h>
+#include <Columns/ColumnVector.h>
+#include <Columns/ColumnDecimal.h>
 
 
 namespace DB
@@ -18,10 +21,15 @@ void callWithType(AsofRowRefs::Type which, F && f)
 {
     switch (which)
     {
-        case AsofRowRefs::Type::key32:  return f(UInt32());
-        case AsofRowRefs::Type::key64:  return f(UInt64());
+        case AsofRowRefs::Type::keyu32:  return f(UInt32());
+        case AsofRowRefs::Type::keyu64:  return f(UInt64());
+        case AsofRowRefs::Type::keyi32:  return f(Int32());
+        case AsofRowRefs::Type::keyi64:  return f(Int64());
         case AsofRowRefs::Type::keyf32: return f(Float32());
         case AsofRowRefs::Type::keyf64: return f(Float64());
+        case AsofRowRefs::Type::keyDecimal32: return f(Decimal32());
+        case AsofRowRefs::Type::keyDecimal64: return f(Decimal64());
+        case AsofRowRefs::Type::keyDecimal128: return f(Decimal128());
     }
 
     __builtin_unreachable();
@@ -49,7 +57,9 @@ void AsofRowRefs::insert(Type type, const IColumn * asof_column, const Block * b
         using T = std::decay_t<decltype(t)>;
         using LookupPtr = typename Entry<T>::LookupPtr;
 
-        auto * column = typeid_cast<const ColumnVector<T> *>(asof_column);
+        using ColumnType = std::conditional_t<IsDecimalNumber<T>, ColumnDecimal<T>, ColumnVector<T>>;
+        auto * column = typeid_cast<const ColumnType *>(asof_column);
+
         T key = column->getElement(row_num);
         auto entry = Entry<T>(key, RowRef(block, row_num));
         std::get<LookupPtr>(lookups)->insert(entry);
@@ -71,7 +81,8 @@ const RowRef * AsofRowRefs::findAsof(Type type, ASOF::Inequality inequality, con
         using EntryType = Entry<T>;
         using LookupPtr = typename EntryType::LookupPtr;
 
-        auto * column = typeid_cast<const ColumnVector<T> *>(asof_column);
+        using ColumnType = std::conditional_t<IsDecimalNumber<T>, ColumnDecimal<T>, ColumnVector<T>>;
+        auto * column = typeid_cast<const ColumnType *>(asof_column);
         T key = column->getElement(row_num);
         auto & typed_lookup = std::get<LookupPtr>(lookups);
 
@@ -90,12 +101,22 @@ std::optional<AsofRowRefs::Type> AsofRowRefs::getTypeSize(const IColumn * asof_c
     if (typeid_cast<const ColumnVector<UInt32> *>(asof_column))
     {
         size = sizeof(UInt32);
-        return Type::key32;
+        return Type::keyu32;
     }
     else if (typeid_cast<const ColumnVector<UInt64> *>(asof_column))
     {
         size = sizeof(UInt64);
-        return Type::key64;
+        return Type::keyu64;
+    }
+    else if (typeid_cast<const ColumnVector<Int32> *>(asof_column))
+    {
+        size = sizeof(Int32);
+        return Type::keyi32;
+    }
+    else if (typeid_cast<const ColumnVector<Int64> *>(asof_column))
+    {
+        size = sizeof(Int64);
+        return Type::keyi64;
     }
     else if (typeid_cast<const ColumnVector<Float32> *>(asof_column))
     {
@@ -107,6 +128,21 @@ std::optional<AsofRowRefs::Type> AsofRowRefs::getTypeSize(const IColumn * asof_c
         size = sizeof(Float64);
         return Type::keyf64;
     }
+    else if (typeid_cast<const ColumnDecimal<Decimal32> *>(asof_column))
+    {
+        size = sizeof(Decimal32);
+        return Type::keyDecimal32;
+    }
+    else if (typeid_cast<const ColumnDecimal<Decimal64> *>(asof_column))
+    {
+        size = sizeof(Decimal64);
+        return Type::keyDecimal64;
+    }
+    else if (typeid_cast<const ColumnDecimal<Decimal128> *>(asof_column))
+    {
+        size = sizeof(Decimal128);
+        return Type::keyDecimal128;
+    }
 
     size = 0;
     return {};

dbms/src/Interpreters/RowRefs.h

@@ -216,15 +216,25 @@ public:
     using Lookups = std::variant<
         Entry<UInt32>::LookupPtr,
         Entry<UInt64>::LookupPtr,
+        Entry<Int32>::LookupPtr,
+        Entry<Int64>::LookupPtr,
         Entry<Float32>::LookupPtr,
-        Entry<Float64>::LookupPtr>;
+        Entry<Float64>::LookupPtr,
+        Entry<Decimal32>::LookupPtr,
+        Entry<Decimal64>::LookupPtr,
+        Entry<Decimal128>::LookupPtr>;
 
     enum class Type
     {
-        key32,
-        key64,
+        keyu32,
+        keyu64,
+        keyi32,
+        keyi64,
         keyf32,
         keyf64,
+        keyDecimal32,
+        keyDecimal64,
+        keyDecimal128,
     };
 
     AsofRowRefs() {}

dbms/src/Interpreters/convertFieldToType.cpp

@@ -11,6 +11,7 @@
 #include <DataTypes/DataTypeFixedString.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
+#include <DataTypes/DataTypeDateTime64.h>
 #include <DataTypes/DataTypeEnum.h>
 #include <DataTypes/DataTypeNullable.h>
 
@@ -146,13 +147,33 @@ UInt64 stringToDateTime(const String & s)
     return UInt64(date_time);
 }
 
+DateTime64::NativeType stringToDateTime64(const String & s, UInt32 scale)
+{
+    ReadBufferFromString in(s);
+    DateTime64 datetime64 {0};
+
+    readDateTime64Text(datetime64, scale, in);
+    if (!in.eof())
+        throw Exception("String is too long for DateTime64: " + s, ErrorCodes::TOO_LARGE_STRING_SIZE);
+
+    return datetime64.value;
+}
+
 Field convertFieldToTypeImpl(const Field & src, const IDataType & type, const IDataType * from_type_hint)
 {
     WhichDataType which_type(type);
     WhichDataType which_from_type;
     if (from_type_hint)
+    {
         which_from_type = WhichDataType(*from_type_hint);
 
+        // This was added to mitigate converting DateTime64-Field (a typedef to a Decimal64) to DataTypeDate64-compatitable type.
+        if (from_type_hint && from_type_hint->equals(type))
+        {
+            return src;
+        }
+    }
+
     /// Conversion between Date and DateTime and vice versa.
     if (which_type.isDate() && which_from_type.isDateTime())
     {
@@ -187,11 +208,12 @@ Field convertFieldToTypeImpl(const Field & src, const IDataType & type, const ID
             return dynamic_cast<const IDataTypeEnum &>(type).castToValue(src);
         }
 
-        if (which_type.isDateOrDateTime() && src.getType() == Field::Types::UInt64)
+        if (which_type.isDateOrDateTime() && !which_type.isDateTime64() && src.getType() == Field::Types::UInt64)
         {
             /// We don't need any conversion UInt64 is under type of Date and DateTime
             return src;
         }
+        // TODO (vnemkov): extra cases for DateTime64: converting from integer, converting from Decimal
 
         if (src.getType() == Field::Types::String)
         {
@@ -205,6 +227,12 @@ Field convertFieldToTypeImpl(const Field & src, const IDataType & type, const ID
                 /// Convert 'YYYY-MM-DD hh:mm:ss' Strings to DateTime
                 return stringToDateTime(src.get<const String &>());
             }
+            else if (which_type.isDateTime64())
+            {
+                const auto date_time64 = typeid_cast<const DataTypeDateTime64 *>(&type);
+                /// Convert 'YYYY-MM-DD hh:mm:ss.NNNNNNNNN' Strings to DateTime
+                return stringToDateTime64(src.get<const String &>(), date_time64->getScale());
+            }
             else if (which_type.isUUID())
             {
                 return stringToUUID(src.get<const String &>());

dbms/src/Parsers/ASTAlterQuery.cpp

@@ -176,12 +176,14 @@ void ASTAlterCommand::formatImpl(
         settings.ostr << " TO ";
         switch (move_destination_type)
         {
-            case MoveDestinationType::DISK:
+            case PartDestinationType::DISK:
                 settings.ostr << "DISK ";
                 break;
-            case MoveDestinationType::VOLUME:
+            case PartDestinationType::VOLUME:
                 settings.ostr << "VOLUME ";
                 break;
+            default:
+                break;
         }
         settings.ostr << quoteString(move_destination_name);
     }

dbms/src/Parsers/ASTAlterQuery.h

@@ -3,6 +3,7 @@
 #include <Parsers/IAST.h>
 #include <Parsers/ASTQueryWithTableAndOutput.h>
 #include <Parsers/ASTQueryWithOnCluster.h>
+#include <Parsers/ASTTTLElement.h>
 
 
 namespace DB
@@ -128,15 +129,9 @@ public:
 
     bool if_exists = false;     /// option for DROP_COLUMN, MODIFY_COLUMN, COMMENT_COLUMN
 
-    enum MoveDestinationType
-    {
-        DISK,
-        VOLUME,
-    };
+    PartDestinationType move_destination_type; /// option for MOVE PART/PARTITION
 
-    MoveDestinationType move_destination_type;
-
-    String move_destination_name;
+    String move_destination_name;             /// option for MOVE PART/PARTITION
 
     /** For FETCH PARTITION - the path in ZK to the shard, from which to download the partition.
      */

dbms/src/Parsers/ASTTTLElement.cpp

@@ -0,0 +1,27 @@
+
+#include <Columns/Collator.h>
+#include <Common/quoteString.h>
+#include <Parsers/ASTTTLElement.h>
+
+
+namespace DB
+{
+
+void ASTTTLElement::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
+{
+    children.front()->formatImpl(settings, state, frame);
+    if (destination_type == PartDestinationType::DISK)
+    {
+        settings.ostr << " TO DISK " << quoteString(destination_name);
+    }
+    else if (destination_type == PartDestinationType::VOLUME)
+    {
+        settings.ostr << " TO VOLUME " << quoteString(destination_name);
+    }
+    else if (destination_type == PartDestinationType::DELETE)
+    {
+        /// It would be better to output "DELETE" here but that will break compatibility with earlier versions.
+    }
+}
+
+}

dbms/src/Parsers/ASTTTLElement.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <Parsers/IAST.h>
+#include <Storages/MergeTree/PartDestinationType.h>
+
+
+namespace DB
+{
+/** Element of TTL expression.
+  */
+class ASTTTLElement : public IAST
+{
+public:
+    PartDestinationType destination_type;
+    String destination_name;
+
+    ASTTTLElement(PartDestinationType destination_type_, const String & destination_name_)
+        : destination_type(destination_type_)
+        , destination_name(destination_name_)
+    {
+    }
+
+    String getID(char) const override { return "TTLElement"; }
+
+    ASTPtr clone() const override
+    {
+        auto clone = std::make_shared<ASTTTLElement>(*this);
+        clone->cloneChildren();
+        return clone;
+    }
+
+protected:
+    void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
+};
+
+}

dbms/src/Parsers/ExpressionElementParsers.cpp

@@ -16,6 +16,7 @@
 #include <Parsers/ASTAsterisk.h>
 #include <Parsers/ASTQualifiedAsterisk.h>
 #include <Parsers/ASTQueryParameter.h>
+#include <Parsers/ASTTTLElement.h>
 #include <Parsers/ASTOrderByElement.h>
 #include <Parsers/ASTSubquery.h>
 #include <Parsers/ASTFunctionWithKeyValueArguments.h>
@@ -1414,6 +1415,42 @@ bool ParserFunctionWithKeyValueArguments::parseImpl(Pos & pos, ASTPtr & node, Ex
     return true;
 }
 
+bool ParserTTLElement::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
+{
+    ParserKeyword s_to_disk("TO DISK");
+    ParserKeyword s_to_volume("TO VOLUME");
+    ParserKeyword s_delete("DELETE");
+    ParserStringLiteral parser_string_literal;
+    ParserExpression parser_exp;
+
+    ASTPtr expr_elem;
+    if (!parser_exp.parse(pos, expr_elem, expected))
+        return false;
+
+    PartDestinationType destination_type = PartDestinationType::DELETE;
+    String destination_name;
+    if (s_to_disk.ignore(pos))
+        destination_type = PartDestinationType::DISK;
+    else if (s_to_volume.ignore(pos))
+        destination_type = PartDestinationType::VOLUME;
+    else
+        s_delete.ignore(pos);
+
+    if (destination_type == PartDestinationType::DISK || destination_type == PartDestinationType::VOLUME)
+    {
+        ASTPtr ast_space_name;
+        if (!parser_string_literal.parse(pos, ast_space_name, expected))
+            return false;
+
+        destination_name = ast_space_name->as<ASTLiteral &>().value.get<const String &>();
+    }
+
+    node = std::make_shared<ASTTTLElement>(destination_type, destination_name);
+    node->children.push_back(expr_elem);
+
+    return true;
+}
+
 bool ParserIdentifierWithOptionalParameters::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
 {
     ParserIdentifier non_parametric;

dbms/src/Parsers/ExpressionElementParsers.h

@@ -320,4 +320,14 @@ protected:
     bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected);
 };
 
+/** Element of TTL expression - same as expression element, but in addition,
+ *   TO DISK 'xxx' | TO VOLUME 'xxx' | DELETE could be specified
+  */
+class ParserTTLElement : public IParserBase
+{
+protected:
+    const char * getName() const { return "element of TTL expression"; }
+    bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected);
+};
+
 }

dbms/src/Parsers/ExpressionListParsers.cpp

@@ -557,6 +557,13 @@ bool ParserOrderByExpressionList::parseImpl(Pos & pos, ASTPtr & node, Expected &
 }
 
 
+bool ParserTTLExpressionList::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
+{
+    return ParserList(std::make_unique<ParserTTLElement>(), std::make_unique<ParserToken>(TokenType::Comma), false)
+        .parse(pos, node, expected);
+}
+
+
 bool ParserNullityChecking::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
 {
     ASTPtr node_comp;

dbms/src/Parsers/ExpressionListParsers.h

@@ -386,6 +386,7 @@ protected:
     bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) override;
 };
 
+
 /// Parser for list of key-value pairs.
 class ParserKeyValuePairsList : public IParserBase
 {
@@ -394,4 +395,12 @@ protected:
     bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) override;
 };
 
+
+class ParserTTLExpressionList : public IParserBase
+{
+protected:
+    const char * getName() const { return "ttl expression"; }
+    bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected);
+};
+
 }

dbms/src/Parsers/ParserAlterQuery.cpp

@@ -87,6 +87,7 @@ bool ParserAlterCommand::parseImpl(Pos & pos, ASTPtr & node, Expected & expected
         /* allow_empty = */ false);
     ParserSetQuery parser_settings(true);
     ParserNameList values_p;
+    ParserTTLExpressionList parser_ttl_list;
 
     if (is_live_view)
     {
@@ -236,9 +237,9 @@ bool ParserAlterCommand::parseImpl(Pos & pos, ASTPtr & node, Expected & expected
             command->part = true;
 
             if (s_to_disk.ignore(pos))
-                command->move_destination_type = ASTAlterCommand::MoveDestinationType::DISK;
+                command->move_destination_type = PartDestinationType::DISK;
             else if (s_to_volume.ignore(pos))
-                command->move_destination_type = ASTAlterCommand::MoveDestinationType::VOLUME;
+                command->move_destination_type = PartDestinationType::VOLUME;
             else
                 return false;
 
@@ -256,9 +257,9 @@ bool ParserAlterCommand::parseImpl(Pos & pos, ASTPtr & node, Expected & expected
             command->type = ASTAlterCommand::MOVE_PARTITION;
 
             if (s_to_disk.ignore(pos))
-                command->move_destination_type = ASTAlterCommand::MoveDestinationType::DISK;
+                command->move_destination_type = PartDestinationType::DISK;
             else if (s_to_volume.ignore(pos))
-                command->move_destination_type = ASTAlterCommand::MoveDestinationType::VOLUME;
+                command->move_destination_type = PartDestinationType::VOLUME;
             else
                 return false;
 
@@ -431,7 +432,7 @@ bool ParserAlterCommand::parseImpl(Pos & pos, ASTPtr & node, Expected & expected
         }
         else if (s_modify_ttl.ignore(pos, expected))
         {
-            if (!parser_exp_elem.parse(pos, command->ttl, expected))
+            if (!parser_ttl_list.parse(pos, command->ttl, expected))
                 return false;
             command->type = ASTAlterCommand::MODIFY_TTL;
         }

dbms/src/Parsers/ParserCreateQuery.cpp

@@ -250,6 +250,7 @@ bool ParserStorage::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
     ParserIdentifierWithOptionalParameters ident_with_optional_params_p;
     ParserExpression expression_p;
     ParserSetQuery settings_p(/* parse_only_internals_ = */ true);
+    ParserTTLExpressionList parser_ttl_list;
 
     ASTPtr engine;
     ASTPtr partition_by;
@@ -303,7 +304,7 @@ bool ParserStorage::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
 
         if (!ttl_table && s_ttl.ignore(pos, expected))
         {
-            if (expression_p.parse(pos, ttl_table, expected))
+            if (parser_ttl_list.parse(pos, ttl_table, expected))
                 continue;
             else
                 return false;

dbms/src/Storages/MergeTree/BackgroundProcessingPool.cpp

@@ -23,17 +23,6 @@ namespace CurrentMetrics
 namespace DB
 {
 
-static constexpr double thread_sleep_seconds = 10;
-static constexpr double thread_sleep_seconds_random_part = 1.0;
-static constexpr double thread_sleep_seconds_if_nothing_to_do = 0.1;
-
-/// For exponential backoff.
-static constexpr double task_sleep_seconds_when_no_work_min = 10;
-static constexpr double task_sleep_seconds_when_no_work_max = 600;
-static constexpr double task_sleep_seconds_when_no_work_multiplier = 1.1;
-static constexpr double task_sleep_seconds_when_no_work_random_part = 1.0;
-
-
 void BackgroundProcessingPoolTaskInfo::wake()
 {
     Poco::Timestamp current_time;
@@ -61,9 +50,13 @@ void BackgroundProcessingPoolTaskInfo::wake()
 }
 
 
-BackgroundProcessingPool::BackgroundProcessingPool(int size_, const char * log_name, const char * thread_name_)
+BackgroundProcessingPool::BackgroundProcessingPool(int size_,
+        const PoolSettings & pool_settings,
+        const char * log_name,
+        const char * thread_name_)
     : size(size_)
     , thread_name(thread_name_)
+    , settings(pool_settings)
 {
     logger = &Logger::get(log_name);
     LOG_INFO(logger, "Create " << log_name << " with " << size << " threads");
@@ -147,7 +140,7 @@ void BackgroundProcessingPool::threadFunction()
         memory_tracker->setMetric(CurrentMetrics::MemoryTrackingInBackgroundProcessingPool);
 
     pcg64 rng(randomSeed());
-    std::this_thread::sleep_for(std::chrono::duration<double>(std::uniform_real_distribution<double>(0, thread_sleep_seconds_random_part)(rng)));
+    std::this_thread::sleep_for(std::chrono::duration<double>(std::uniform_real_distribution<double>(0, settings.thread_sleep_seconds_random_part)(rng)));
 
     while (!shutdown)
     {
@@ -182,8 +175,8 @@ void BackgroundProcessingPool::threadFunction()
             {
                 std::unique_lock lock(tasks_mutex);
                 wake_event.wait_for(lock,
-                    std::chrono::duration<double>(thread_sleep_seconds
-                        + std::uniform_real_distribution<double>(0, thread_sleep_seconds_random_part)(rng)));
+                    std::chrono::duration<double>(settings.thread_sleep_seconds
+                        + std::uniform_real_distribution<double>(0, settings.thread_sleep_seconds_random_part)(rng)));
                 continue;
             }
 
@@ -193,7 +186,7 @@ void BackgroundProcessingPool::threadFunction()
             {
                 std::unique_lock lock(tasks_mutex);
                 wake_event.wait_for(lock, std::chrono::microseconds(
-                    min_time - current_time + std::uniform_int_distribution<uint64_t>(0, thread_sleep_seconds_random_part * 1000000)(rng)));
+                    min_time - current_time + std::uniform_int_distribution<uint64_t>(0, settings.thread_sleep_seconds_random_part * 1000000)(rng)));
             }
 
             std::shared_lock rlock(task->rwlock);
@@ -231,11 +224,11 @@ void BackgroundProcessingPool::threadFunction()
             Poco::Timestamp next_time_to_execute;   /// current time
             if (task_result == TaskResult::ERROR)
                 next_time_to_execute += 1000000 * (std::min(
-                        task_sleep_seconds_when_no_work_max,
-                        task_sleep_seconds_when_no_work_min * std::pow(task_sleep_seconds_when_no_work_multiplier, task->count_no_work_done))
-                    + std::uniform_real_distribution<double>(0, task_sleep_seconds_when_no_work_random_part)(rng));
+                        settings.task_sleep_seconds_when_no_work_max,
+                        settings.task_sleep_seconds_when_no_work_min * std::pow(settings.task_sleep_seconds_when_no_work_multiplier, task->count_no_work_done))
+                    + std::uniform_real_distribution<double>(0, settings.task_sleep_seconds_when_no_work_random_part)(rng));
             else if (task_result == TaskResult::NOTHING_TO_DO)
-                next_time_to_execute += 1000000 * thread_sleep_seconds_if_nothing_to_do;
+                next_time_to_execute += 1000000 * settings.thread_sleep_seconds_if_nothing_to_do;
 
             tasks.erase(task->iterator);
             task->iterator = tasks.emplace(next_time_to_execute, task);

dbms/src/Storages/MergeTree/BackgroundProcessingPool.h

@@ -14,6 +14,7 @@
 #include <Core/Types.h>
 #include <Common/CurrentThread.h>
 #include <Common/ThreadPool.h>
+#include <Poco/Util/AbstractConfiguration.h>
 
 
 namespace DB
@@ -46,7 +47,23 @@ public:
     using TaskHandle = std::shared_ptr<TaskInfo>;
 
 
+    struct PoolSettings
+    {
+        double thread_sleep_seconds = 10;
+        double thread_sleep_seconds_random_part = 1.0;
+        double thread_sleep_seconds_if_nothing_to_do = 0.1;
+
+        /// For exponential backoff.
+        double task_sleep_seconds_when_no_work_min = 10;
+        double task_sleep_seconds_when_no_work_max = 600;
+        double task_sleep_seconds_when_no_work_multiplier = 1.1;
+        double task_sleep_seconds_when_no_work_random_part = 1.0;
+
+        PoolSettings() noexcept {}
+    };
+
     BackgroundProcessingPool(int size_,
+        const PoolSettings & pool_settings = {},
         const char * log_name = "BackgroundProcessingPool",
         const char * thread_name_ = "BackgrProcPool");
 
@@ -84,6 +101,9 @@ protected:
     ThreadGroupStatusPtr thread_group;
 
     void threadFunction();
+
+private:
+    PoolSettings settings;
 };
 
 

dbms/src/Storages/MergeTree/MergeTreeData.cpp

@@ -38,6 +38,7 @@
 #include <Common/Increment.h>
 #include <Common/SimpleIncrement.h>
 #include <Common/escapeForFileName.h>
+#include <Common/quoteString.h>
 #include <Common/StringUtils/StringUtils.h>
 #include <Common/Stopwatch.h>
 #include <Common/typeid_cast.h>
@@ -70,6 +71,12 @@ namespace CurrentMetrics
 }
 
 
+namespace
+{
+    constexpr UInt64 RESERVATION_MIN_ESTIMATION_SIZE = 1u * 1024u * 1024u; /// 1MB
+}
+
+
 namespace DB
 {
 
@@ -124,7 +131,6 @@ MergeTreeData::MergeTreeData(
     , merging_params(merging_params_)
     , partition_by_ast(partition_by_ast_)
     , sample_by_ast(sample_by_ast_)
-    , ttl_table_ast(ttl_table_ast_)
     , require_part_metadata(require_part_metadata_)
     , database_name(database_)
     , table_name(table_)
@@ -566,15 +572,17 @@ void checkTTLExpression(const ExpressionActionsPtr & ttl_expression, const Strin
 void MergeTreeData::setTTLExpressions(const ColumnsDescription::ColumnTTLs & new_column_ttls,
         const ASTPtr & new_ttl_table_ast, bool only_check)
 {
-    auto create_ttl_entry = [this](ASTPtr ttl_ast) -> TTLEntry
+    auto create_ttl_entry = [this](ASTPtr ttl_ast)
     {
+        TTLEntry result;
+
         auto syntax_result = SyntaxAnalyzer(global_context).analyze(ttl_ast, getColumns().getAllPhysical());
-        auto expr = ExpressionAnalyzer(ttl_ast, syntax_result, global_context).getActions(false);
+        result.expression = ExpressionAnalyzer(ttl_ast, syntax_result, global_context).getActions(false);
+        result.destination_type = PartDestinationType::DELETE;
+        result.result_column = ttl_ast->getColumnName();
 
-        String result_column = ttl_ast->getColumnName();
-        checkTTLExpression(expr, result_column);
-
-        return {expr, result_column};
+        checkTTLExpression(result.expression, result.result_column);
+        return result;
     };
 
     if (!new_column_ttls.empty())
@@ -592,23 +600,49 @@ void MergeTreeData::setTTLExpressions(const ColumnsDescription::ColumnTTLs & new
         for (const auto & [name, ast] : new_column_ttls)
         {
             if (columns_ttl_forbidden.count(name))
-                throw Exception("Trying to set ttl for key column " + name, ErrorCodes::ILLEGAL_COLUMN);
+                throw Exception("Trying to set TTL for key column " + name, ErrorCodes::ILLEGAL_COLUMN);
             else
             {
                 auto new_ttl_entry = create_ttl_entry(ast);
                 if (!only_check)
-                    ttl_entries_by_name.emplace(name, new_ttl_entry);
+                    column_ttl_entries_by_name.emplace(name, new_ttl_entry);
             }
         }
     }
 
     if (new_ttl_table_ast)
     {
-        auto new_ttl_table_entry = create_ttl_entry(new_ttl_table_ast);
-        if (!only_check)
+        bool seen_delete_ttl = false;
+        for (auto ttl_element_ptr : new_ttl_table_ast->children)
         {
-            ttl_table_ast = new_ttl_table_ast;
-            ttl_table_entry = new_ttl_table_entry;
+            ASTTTLElement & ttl_element = static_cast<ASTTTLElement &>(*ttl_element_ptr);
+            if (ttl_element.destination_type == PartDestinationType::DELETE)
+            {
+                if (seen_delete_ttl)
+                {
+                    throw Exception("More than one DELETE TTL expression is not allowed", ErrorCodes::BAD_TTL_EXPRESSION);
+                }
+
+                auto new_ttl_table_entry = create_ttl_entry(ttl_element.children[0]);
+                if (!only_check)
+                {
+                    ttl_table_ast = ttl_element.children[0];
+                    ttl_table_entry = new_ttl_table_entry;
+                }
+
+                seen_delete_ttl = true;
+            }
+            else
+            {
+                auto new_ttl_entry = create_ttl_entry(ttl_element.children[0]);
+                if (!only_check)
+                {
+                    new_ttl_entry.entry_ast = ttl_element_ptr;
+                    new_ttl_entry.destination_type = ttl_element.destination_type;
+                    new_ttl_entry.destination_name = ttl_element.destination_name;
+                    move_ttl_entries.emplace_back(std::move(new_ttl_entry));
+                }
+            }
         }
     }
 }
@@ -3096,20 +3130,138 @@ MergeTreeData::MutableDataPartsVector MergeTreeData::tryLoadPartsToAttach(const
     return loaded_parts;
 }
 
-DiskSpace::ReservationPtr MergeTreeData::reserveSpace(UInt64 expected_size)
+namespace
 {
-    constexpr UInt64 RESERVATION_MIN_ESTIMATION_SIZE = 1u * 1024u * 1024u; /// 1MB
 
-    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
-
-    auto reservation = storage_policy->reserve(expected_size);
+inline DiskSpace::ReservationPtr checkAndReturnReservation(UInt64 expected_size, DiskSpace::ReservationPtr reservation)
+{
     if (reservation)
         return reservation;
 
-    throw Exception("Cannot reserve " + formatReadableSizeWithBinarySuffix(expected_size) + ", not enough space.",
+    throw Exception("Cannot reserve " + formatReadableSizeWithBinarySuffix(expected_size) + ", not enough space",
                     ErrorCodes::NOT_ENOUGH_SPACE);
 }
 
+}
+
+DiskSpace::ReservationPtr MergeTreeData::reserveSpace(UInt64 expected_size) const
+{
+    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
+
+    auto reservation = storage_policy->reserve(expected_size);
+
+    return checkAndReturnReservation(expected_size, std::move(reservation));
+}
+
+DiskSpace::ReservationPtr MergeTreeData::reserveSpace(UInt64 expected_size, DiskSpace::SpacePtr space) const
+{
+    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
+
+    auto reservation = tryReserveSpace(expected_size, space);
+
+    return checkAndReturnReservation(expected_size, std::move(reservation));
+}
+
+DiskSpace::ReservationPtr MergeTreeData::tryReserveSpace(UInt64 expected_size, DiskSpace::SpacePtr space) const
+{
+    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
+
+    return space->reserve(expected_size);
+}
+
+DiskSpace::ReservationPtr MergeTreeData::reserveSpacePreferringTTLRules(UInt64 expected_size,
+        const MergeTreeDataPart::TTLInfos & ttl_infos,
+        time_t time_of_move) const
+{
+    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
+
+    DiskSpace::ReservationPtr reservation = tryReserveSpacePreferringTTLRules(expected_size, ttl_infos, time_of_move);
+
+    return checkAndReturnReservation(expected_size, std::move(reservation));
+}
+
+DiskSpace::ReservationPtr MergeTreeData::tryReserveSpacePreferringTTLRules(UInt64 expected_size,
+        const MergeTreeDataPart::TTLInfos & ttl_infos,
+        time_t time_of_move) const
+{
+    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
+
+    DiskSpace::ReservationPtr reservation;
+
+    auto ttl_entry = selectTTLEntryForTTLInfos(ttl_infos, time_of_move);
+    if (ttl_entry != nullptr)
+    {
+        DiskSpace::SpacePtr destination_ptr = ttl_entry->getDestination(storage_policy);
+        if (!destination_ptr)
+        {
+            if (ttl_entry->destination_type == PartDestinationType::VOLUME)
+                LOG_WARNING(log, "Would like to reserve space on volume '"
+                        << ttl_entry->destination_name << "' by TTL rule of table '"
+                        << log_name << "' but volume was not found");
+            else if (ttl_entry->destination_type == PartDestinationType::DISK)
+                LOG_WARNING(log, "Would like to reserve space on disk '"
+                        << ttl_entry->destination_name << "' by TTL rule of table '"
+                        << log_name << "' but disk was not found");
+        }
+        else
+        {
+            reservation = destination_ptr->reserve(expected_size);
+            if (reservation)
+                return reservation;
+        }
+    }
+
+    reservation = storage_policy->reserve(expected_size);
+
+    return reservation;
+}
+
+DiskSpace::SpacePtr MergeTreeData::TTLEntry::getDestination(const DiskSpace::StoragePolicyPtr & policy) const
+{
+    if (destination_type == PartDestinationType::VOLUME)
+        return policy->getVolumeByName(destination_name);
+    else if (destination_type == PartDestinationType::DISK)
+        return policy->getDiskByName(destination_name);
+    else
+        return {};
+}
+
+bool MergeTreeData::TTLEntry::isPartInDestination(const DiskSpace::StoragePolicyPtr & policy, const MergeTreeDataPart & part) const
+{
+    if (destination_type == PartDestinationType::VOLUME)
+    {
+        for (const auto & disk : policy->getVolumeByName(destination_name)->disks)
+            if (disk->getName() == part.disk->getName())
+                return true;
+    }
+    else if (destination_type == PartDestinationType::DISK)
+        return policy->getDiskByName(destination_name)->getName() == part.disk->getName();
+    return false;
+}
+
+const MergeTreeData::TTLEntry * MergeTreeData::selectTTLEntryForTTLInfos(
+        const MergeTreeDataPart::TTLInfos & ttl_infos,
+        time_t time_of_move) const
+{
+    const MergeTreeData::TTLEntry * result = nullptr;
+    /// Prefer TTL rule which went into action last.
+    time_t max_max_ttl = 0;
+
+    for (const auto & ttl_entry : move_ttl_entries)
+    {
+        auto ttl_info_it = ttl_infos.moves_ttl.find(ttl_entry.result_column);
+        if (ttl_info_it != ttl_infos.moves_ttl.end()
+                && ttl_info_it->second.max <= time_of_move
+                && max_max_ttl <= ttl_info_it->second.max)
+        {
+            result = &ttl_entry;
+            max_max_ttl = ttl_info_it->second.max;
+        }
+    }
+
+    return result;
+}
+
 MergeTreeData::DataParts MergeTreeData::getDataParts(const DataPartStates & affordable_states) const
 {
     DataParts res;
@@ -3289,12 +3441,7 @@ MergeTreeData::MutableDataPartPtr MergeTreeData::cloneAndLoadDataPartOnSameDisk(
     String dst_part_name = src_part->getNewName(dst_part_info);
     String tmp_dst_part_name = tmp_part_prefix + dst_part_name;
 
-    auto reservation = src_part->disk->reserve(src_part->bytes_on_disk);
-    if (!reservation)
-    {
-        throw Exception("Cannot reserve " + formatReadableSizeWithBinarySuffix(src_part->bytes_on_disk) + ", not enough space",
-                    ErrorCodes::NOT_ENOUGH_SPACE);
-    }
+    auto reservation = reserveSpace(src_part->bytes_on_disk, src_part->disk);
     String dst_part_path = getFullPathOnDisk(reservation->getDisk());
     Poco::Path dst_part_absolute_path = Poco::Path(dst_part_path + tmp_dst_part_name).absolute();
     Poco::Path src_part_absolute_path = Poco::Path(src_part->getFullPath()).absolute();

dbms/src/Storages/MergeTree/MergeTreeData.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Common/SimpleIncrement.h>
+#include <Common/DiskSpaceMonitor.h>
 #include <Interpreters/Context.h>
 #include <Interpreters/ExpressionActions.h>
 #include <Storages/IStorage.h>
@@ -9,6 +10,7 @@
 #include <Storages/MergeTree/MergeTreeSettings.h>
 #include <Storages/MergeTree/MergeTreeMutationStatus.h>
 #include <Storages/MergeTree/MergeList.h>
+#include <Storages/MergeTree/PartDestinationType.h>
 #include <IO/ReadBufferFromString.h>
 #include <IO/WriteBufferFromFile.h>
 #include <IO/ReadBufferFromFile.h>
@@ -19,7 +21,6 @@
 #include <Storages/IndicesDescription.h>
 #include <Storages/MergeTree/MergeTreePartsMover.h>
 #include <Interpreters/PartLog.h>
-#include <Common/DiskSpaceMonitor.h>
 
 #include <boost/multi_index_container.hpp>
 #include <boost/multi_index/ordered_index.hpp>
@@ -565,7 +566,7 @@ public:
     /// All MergeTreeData children have settings.
     void checkSettingCanBeChanged(const String & setting_name) const override;
 
-    /// Remove columns, that have been markedd as empty after zeroing values with expired ttl
+    /// Remove columns, that have been marked as empty after zeroing values with expired ttl
     void removeEmptyColumnsFromPart(MergeTreeData::MutableDataPartPtr & data_part);
 
     /// Freezes all parts.
@@ -587,7 +588,7 @@ public:
     bool hasPrimaryKey() const { return !primary_key_columns.empty(); }
     bool hasSkipIndices() const { return !skip_indices.empty(); }
     bool hasTableTTL() const { return ttl_table_ast != nullptr; }
-    bool hasAnyColumnTTL() const { return !ttl_entries_by_name.empty(); }
+    bool hasAnyColumnTTL() const { return !column_ttl_entries_by_name.empty(); }
 
     /// Check that the part is not broken and calculate the checksums for it if they are not present.
     MutableDataPartPtr loadPartAndFixMetadata(const DiskSpace::DiskPtr & disk, const String & relative_path);
@@ -673,9 +674,20 @@ public:
     using PathsWithDisks = std::vector<PathWithDisk>;
     PathsWithDisks getDataPathsWithDisks() const;
 
-    /// Reserves space at least 1MB
-    DiskSpace::ReservationPtr reserveSpace(UInt64 expected_size);
+    /// Reserves space at least 1MB.
+    DiskSpace::ReservationPtr reserveSpace(UInt64 expected_size) const;
 
+    /// Reserves space at least 1MB on specific disk or volume.
+    DiskSpace::ReservationPtr reserveSpace(UInt64 expected_size, DiskSpace::SpacePtr space) const;
+    DiskSpace::ReservationPtr tryReserveSpace(UInt64 expected_size, DiskSpace::SpacePtr space) const;
+
+    /// Reserves space at least 1MB preferring best destination according to `ttl_infos`.
+    DiskSpace::ReservationPtr reserveSpacePreferringTTLRules(UInt64 expected_size,
+                                                                const MergeTreeDataPart::TTLInfos & ttl_infos,
+                                                                time_t time_of_move) const;
+    DiskSpace::ReservationPtr tryReserveSpacePreferringTTLRules(UInt64 expected_size,
+                                                                const MergeTreeDataPart::TTLInfos & ttl_infos,
+                                                                time_t time_of_move) const;
     /// Choose disk with max available free space
     /// Reserves 0 bytes
     DiskSpace::ReservationPtr makeEmptyReservationOnLargestDisk() { return storage_policy->makeEmptyReservationOnLargestDisk(); }
@@ -719,12 +731,27 @@ public:
     {
         ExpressionActionsPtr expression;
         String result_column;
+
+        /// Name and type of a destination are only valid in table-level context.
+        PartDestinationType destination_type;
+        String destination_name;
+
+        ASTPtr entry_ast;
+
+        /// Returns destination disk or volume for this rule.
+        DiskSpace::SpacePtr getDestination(const DiskSpace::StoragePolicyPtr & policy) const;
+
+        /// Checks if given part already belongs destination disk or volume for this rule.
+        bool isPartInDestination(const DiskSpace::StoragePolicyPtr & policy, const MergeTreeDataPart & part) const;
     };
 
+    const TTLEntry * selectTTLEntryForTTLInfos(const MergeTreeDataPart::TTLInfos & ttl_infos, time_t time_of_move) const;
+
     using TTLEntriesByName = std::unordered_map<String, TTLEntry>;
-    TTLEntriesByName ttl_entries_by_name;
+    TTLEntriesByName column_ttl_entries_by_name;
 
     TTLEntry ttl_table_entry;
+    std::vector<TTLEntry> move_ttl_entries;
 
     String sampling_expr_column_name;
     Names columns_required_for_sampling;

dbms/src/Storages/MergeTree/MergeTreeDataPartTTLInfo.cpp

@@ -1,6 +1,7 @@
 #include <Storages/MergeTree/MergeTreeDataPartTTLInfo.h>
 #include <IO/ReadHelpers.h>
 #include <IO/WriteHelpers.h>
+#include <Common/quoteString.h>
 
 #include <common/JSON.h>
 
@@ -15,10 +16,16 @@ void MergeTreeDataPartTTLInfos::update(const MergeTreeDataPartTTLInfos & other_i
         updatePartMinMaxTTL(ttl_info.min, ttl_info.max);
     }
 
+    for (const auto & [expression, ttl_info] : other_infos.moves_ttl)
+    {
+        moves_ttl[expression].update(ttl_info);
+    }
+
     table_ttl.update(other_infos.table_ttl);
     updatePartMinMaxTTL(table_ttl.min, table_ttl.max);
 }
 
+
 void MergeTreeDataPartTTLInfos::read(ReadBuffer & in)
 {
     String json_str;
@@ -28,7 +35,7 @@ void MergeTreeDataPartTTLInfos::read(ReadBuffer & in)
     JSON json(json_str);
     if (json.has("columns"))
     {
-        JSON columns = json["columns"];
+        const JSON & columns = json["columns"];
         for (auto col : columns)
         {
             MergeTreeDataPartTTLInfo ttl_info;
@@ -42,14 +49,27 @@ void MergeTreeDataPartTTLInfos::read(ReadBuffer & in)
     }
     if (json.has("table"))
     {
-        JSON table = json["table"];
+        const JSON & table = json["table"];
         table_ttl.min = table["min"].getUInt();
         table_ttl.max = table["max"].getUInt();
 
         updatePartMinMaxTTL(table_ttl.min, table_ttl.max);
     }
+    if (json.has("moves"))
+    {
+        const JSON & moves = json["moves"];
+        for (auto move : moves)
+        {
+            MergeTreeDataPartTTLInfo ttl_info;
+            ttl_info.min = move["min"].getUInt();
+            ttl_info.max = move["max"].getUInt();
+            String expression = move["expression"].getString();
+            moves_ttl.emplace(expression, ttl_info);
+        }
+    }
 }
 
+
 void MergeTreeDataPartTTLInfos::write(WriteBuffer & out) const
 {
     writeString("ttl format version: 1\n", out);
@@ -62,9 +82,9 @@ void MergeTreeDataPartTTLInfos::write(WriteBuffer & out) const
             if (it != columns_ttl.begin())
                 writeString(",", out);
 
-            writeString("{\"name\":\"", out);
-            writeString(it->first, out);
-            writeString("\",\"min\":", out);
+            writeString("{\"name\":", out);
+            writeString(doubleQuoteString(it->first), out);
+            writeString(",\"min\":", out);
             writeIntText(it->second.min, out);
             writeString(",\"max\":", out);
             writeIntText(it->second.max, out);
@@ -82,6 +102,26 @@ void MergeTreeDataPartTTLInfos::write(WriteBuffer & out) const
         writeIntText(table_ttl.max, out);
         writeString("}", out);
     }
+    if (!moves_ttl.empty())
+    {
+        if (!columns_ttl.empty() || table_ttl.min)
+            writeString(",", out);
+        writeString("\"moves\":[", out);
+        for (auto it = moves_ttl.begin(); it != moves_ttl.end(); ++it)
+        {
+            if (it != moves_ttl.begin())
+                writeString(",", out);
+
+            writeString("{\"expression\":", out);
+            writeString(doubleQuoteString(it->first), out);
+            writeString(",\"min\":", out);
+            writeIntText(it->second.min, out);
+            writeString(",\"max\":", out);
+            writeIntText(it->second.max, out);
+            writeString("}", out);
+        }
+        writeString("]", out);
+    }
     writeString("}", out);
 }
 

dbms/src/Storages/MergeTree/MergeTreeDataPartTTLInfo.h

@@ -35,9 +35,14 @@ struct MergeTreeDataPartTTLInfos
 {
     std::unordered_map<String, MergeTreeDataPartTTLInfo> columns_ttl;
     MergeTreeDataPartTTLInfo table_ttl;
+
+    /// `part_min_ttl` and `part_max_ttl` are TTLs which are used for selecting parts
+    /// to merge in order to remove expired rows.    
     time_t part_min_ttl = 0;
     time_t part_max_ttl = 0;
 
+    std::unordered_map<String, MergeTreeDataPartTTLInfo> moves_ttl;
+
     void read(ReadBuffer & in);
     void write(WriteBuffer & out) const;
     void update(const MergeTreeDataPartTTLInfos & other_infos);
@@ -50,6 +55,11 @@ struct MergeTreeDataPartTTLInfos
         if (time_max && (!part_max_ttl || time_max > part_max_ttl))
             part_max_ttl = time_max;
     }
+
+    bool empty()
+    {
+        return !part_min_ttl && moves_ttl.empty();
+    }
 };
 
 }

dbms/src/Storages/MergeTree/MergeTreeDataWriter.cpp

@@ -75,12 +75,17 @@ void buildScatterSelector(
 }
 
 /// Computes ttls and updates ttl infos
-void updateTTL(const MergeTreeData::TTLEntry & ttl_entry, MergeTreeDataPart::TTLInfos & ttl_infos, Block & block, const String & column_name)
+void updateTTL(const MergeTreeData::TTLEntry & ttl_entry,
+    MergeTreeDataPart::TTLInfos & ttl_infos,
+    DB::MergeTreeDataPartTTLInfo & ttl_info,
+    Block & block, bool update_part_min_max_ttls)
 {
+    bool remove_column = false;
     if (!block.has(ttl_entry.result_column))
+    {
         ttl_entry.expression->execute(block);
-
-    auto & ttl_info = (column_name.empty() ? ttl_infos.table_ttl : ttl_infos.columns_ttl[column_name]);
+        remove_column = true;
+    }
 
     const auto & current = block.getByName(ttl_entry.result_column);
 
@@ -113,7 +118,11 @@ void updateTTL(const MergeTreeData::TTLEntry & ttl_entry, MergeTreeDataPart::TTL
     else
         throw Exception("Unexpected type of result TTL column", ErrorCodes::LOGICAL_ERROR);
 
-    ttl_infos.updatePartMinMaxTTL(ttl_info.min, ttl_info.max);
+    if (update_part_min_max_ttls)
+        ttl_infos.updatePartMinMaxTTL(ttl_info.min, ttl_info.max);
+
+    if (remove_column)
+        block.erase(ttl_entry.result_column);
 }
 
 }
@@ -212,10 +221,14 @@ MergeTreeData::MutableDataPartPtr MergeTreeDataWriter::writeTempPart(BlockWithPa
     else
         part_name = new_part_info.getPartName();
 
-    /// Size of part would not be grater than block.bytes() + epsilon
+    /// Size of part would not be greater than block.bytes() + epsilon
     size_t expected_size = block.bytes();
-    auto reservation = data.reserveSpace(expected_size);
 
+    DB::MergeTreeDataPart::TTLInfos move_ttl_infos;
+    for (const auto & ttl_entry : data.move_ttl_entries)
+        updateTTL(ttl_entry, move_ttl_infos, move_ttl_infos.moves_ttl[ttl_entry.result_column], block, false);
+
+    DiskSpace::ReservationPtr reservation = data.reserveSpacePreferringTTLRules(expected_size, move_ttl_infos, time(nullptr));
 
     MergeTreeData::MutableDataPartPtr new_data_part =
         std::make_shared<MergeTreeData::DataPart>(data, reservation->getDisk(), part_name, new_part_info);
@@ -251,7 +264,7 @@ MergeTreeData::MutableDataPartPtr MergeTreeDataWriter::writeTempPart(BlockWithPa
 
     ProfileEvents::increment(ProfileEvents::MergeTreeDataWriterBlocks);
 
-    /// Sort.
+    /// Sort
     IColumn::Permutation * perm_ptr = nullptr;
     IColumn::Permutation perm;
     if (!sort_description.empty())
@@ -266,10 +279,12 @@ MergeTreeData::MutableDataPartPtr MergeTreeDataWriter::writeTempPart(BlockWithPa
     }
 
     if (data.hasTableTTL())
-        updateTTL(data.ttl_table_entry, new_data_part->ttl_infos, block, "");
+        updateTTL(data.ttl_table_entry, new_data_part->ttl_infos, new_data_part->ttl_infos.table_ttl, block, true);
 
-    for (const auto & [name, ttl_entry] : data.ttl_entries_by_name)
-        updateTTL(ttl_entry, new_data_part->ttl_infos, block, name);
+    for (const auto & [name, ttl_entry] : data.column_ttl_entries_by_name)
+        updateTTL(ttl_entry, new_data_part->ttl_infos, new_data_part->ttl_infos.columns_ttl[name], block, true);
+
+    new_data_part->ttl_infos.update(move_ttl_infos);
 
     /// This effectively chooses minimal compression method:
     ///  either default lz4 or compression method with zero thresholds on absolute and relative part size.

dbms/src/Storages/MergeTree/MergeTreePartsMover.cpp

@@ -52,11 +52,14 @@ public:
         elems.emplace(part);
         current_size_sum += part->bytes_on_disk;
 
-        while (!elems.empty() && (current_size_sum - (*elems.begin())->bytes_on_disk >= required_size_sum))
-        {
-            current_size_sum -= (*elems.begin())->bytes_on_disk;
-            elems.erase(elems.begin());
-        }
+        removeRedundantElements();
+    }
+
+    /// Weaken requirements on size
+    void decreaseRequiredSizeAndRemoveRedundantParts(UInt64 size_decrease)
+    {
+        required_size_sum -= std::min(size_decrease, required_size_sum);
+        removeRedundantElements();
     }
 
     /// Returns parts ordered by size
@@ -67,6 +70,16 @@ public:
             res.push_back(elem);
         return res;
     }
+
+private:
+    void removeRedundantElements()
+    {
+        while (!elems.empty() && (current_size_sum - (*elems.begin())->bytes_on_disk >= required_size_sum))
+        {
+            current_size_sum -= (*elems.begin())->bytes_on_disk;
+            elems.erase(elems.begin());
+        }
+    }
 };
 
 }
@@ -85,46 +98,70 @@ bool MergeTreePartsMover::selectPartsForMove(
     const auto & policy = data->getStoragePolicy();
     const auto & volumes = policy->getVolumes();
 
-    /// Do not check if policy has one volume
-    if (volumes.size() == 1)
-        return false;
-
-    /// Do not check last volume
-    for (size_t i = 0; i != volumes.size() - 1; ++i)
+    if (volumes.size() > 0)
     {
-        for (const auto & disk : volumes[i]->disks)
+        /// Do not check last volume
+        for (size_t i = 0; i != volumes.size() - 1; ++i)
         {
-            UInt64 required_available_space = disk->getTotalSpace() * policy->getMoveFactor();
-            UInt64 unreserved_space = disk->getUnreservedSpace();
+            for (const auto & disk : volumes[i]->disks)
+            {
+                UInt64 required_maximum_available_space = disk->getTotalSpace() * policy->getMoveFactor();
+                UInt64 unreserved_space = disk->getUnreservedSpace();
 
-            if (required_available_space > unreserved_space)
-                need_to_move.emplace(disk, required_available_space - unreserved_space);
+                if (unreserved_space < required_maximum_available_space)
+                    need_to_move.emplace(disk, required_maximum_available_space - unreserved_space);
+            }
         }
     }
 
+    time_t time_of_move = time(nullptr);
+
     for (const auto & part : data_parts)
     {
         String reason;
-        /// Don't report message to log, because logging is excessive
+        /// Don't report message to log, because logging is excessive.
         if (!can_move(part, &reason))
             continue;
 
+        const MergeTreeData::TTLEntry * ttl_entry_ptr = part->storage.selectTTLEntryForTTLInfos(part->ttl_infos, time_of_move);
         auto to_insert = need_to_move.find(part->disk);
-        if (to_insert != need_to_move.end())
-            to_insert->second.add(part);
+        DiskSpace::ReservationPtr reservation;
+        if (ttl_entry_ptr)
+        {
+            auto destination = ttl_entry_ptr->getDestination(policy);
+            if (destination && !ttl_entry_ptr->isPartInDestination(policy, *part))
+                reservation = part->storage.tryReserveSpace(part->bytes_on_disk, ttl_entry_ptr->getDestination(policy));
+        }
+
+        if (reservation) /// Found reservation by TTL rule.
+        {
+            parts_to_move.emplace_back(part, std::move(reservation));
+            /// If table TTL rule satisfies on this part, won't apply policy rules on it.
+            /// In order to not over-move, we need to "release" required space on this disk,
+            /// possibly to zero.
+            if (to_insert != need_to_move.end())
+            {
+                to_insert->second.decreaseRequiredSizeAndRemoveRedundantParts(part->bytes_on_disk);
+            }
+        }
+        else
+        {
+            if (to_insert != need_to_move.end())
+                to_insert->second.add(part);
+        }
     }
 
     for (auto && move : need_to_move)
     {
-        auto min_volume_priority = policy->getVolumeIndexByDisk(move.first) + 1;
+        auto min_volume_index = policy->getVolumeIndexByDisk(move.first) + 1;
         for (auto && part : move.second.getAccumulatedParts())
         {
-            auto reservation = policy->reserve(part->bytes_on_disk, min_volume_priority);
+            auto reservation = policy->reserve(part->bytes_on_disk, min_volume_index);
             if (!reservation)
             {
-                /// Next parts to move from this disk has greater size and same min volume priority
-                /// There are no space for them
-                /// But it can be possible to move data from other disks
+                /// Next parts to move from this disk has greater size and same min volume index.
+                /// There are no space for them.
+                /// But it can be possible to move data from other disks.
                 break;
             }
             parts_to_move.emplace_back(part, std::move(reservation));

dbms/src/Storages/MergeTree/MergedBlockOutputStream.cpp

@@ -186,7 +186,7 @@ void MergedBlockOutputStream::writeSuffixAndFinalizePart(
         checksums.files["count.txt"].file_hash = count_out_hashing.getHash();
     }
 
-    if (new_part->ttl_infos.part_min_ttl)
+    if (!new_part->ttl_infos.empty())
     {
         /// Write a file with ttl infos in json format.
         WriteBufferFromFile out(part_path + "ttl.txt", 4096);

dbms/src/Storages/MergeTree/PartDestinationType.h

@@ -0,0 +1,14 @@
+#pragma once
+
+
+namespace DB
+{
+
+enum class PartDestinationType
+{
+    DISK,
+    VOLUME,
+    DELETE,
+};
+
+}

dbms/src/Storages/MergeTree/ReplicatedMergeTreeTableMetadata.cpp

@@ -5,6 +5,7 @@
 #include <Parsers/ExpressionListParsers.h>
 #include <IO/Operators.h>
 
+
 namespace DB
 {
 
@@ -47,6 +48,16 @@ ReplicatedMergeTreeTableMetadata::ReplicatedMergeTreeTableMetadata(const MergeTr
         partition_key = formattedAST(MergeTreeData::extractKeyExpressionList(data.partition_by_ast));
 
     ttl_table = formattedAST(data.ttl_table_ast);
+
+    std::ostringstream ttl_move_stream;
+    for (const auto & ttl_entry : data.move_ttl_entries)
+    {
+        if (ttl_move_stream.tellp() > 0)
+            ttl_move_stream << ", ";
+        ttl_move_stream << formattedAST(ttl_entry.entry_ast);
+    }
+    ttl_move = ttl_move_stream.str();
+
     skip_indices = data.getIndices().toString();
     if (data.canUseAdaptiveGranularity())
         index_granularity_bytes = data_settings->index_granularity_bytes;
@@ -78,6 +89,9 @@ void ReplicatedMergeTreeTableMetadata::write(WriteBuffer & out) const
     if (!ttl_table.empty())
         out << "ttl: " << ttl_table << "\n";
 
+    if (!ttl_move.empty())
+        out << "move ttl: " << ttl_move << "\n";
+
     if (!skip_indices.empty())
         out << "indices: " << skip_indices << "\n";
 
@@ -119,6 +133,9 @@ void ReplicatedMergeTreeTableMetadata::read(ReadBuffer & in)
     if (checkString("ttl: ", in))
         in >> ttl_table >> "\n";
 
+    if (checkString("move ttl: ", in))
+        in >> ttl_move >> "\n";
+
     if (checkString("indices: ", in))
         in >> skip_indices >> "\n";
 
@@ -223,12 +240,27 @@ ReplicatedMergeTreeTableMetadata::checkAndFindDiff(const ReplicatedMergeTreeTabl
         }
         else
             throw Exception(
-                    "Existing table metadata in ZooKeeper differs in ttl."
+                    "Existing table metadata in ZooKeeper differs in TTL."
                     " Stored in ZooKeeper: " + from_zk.ttl_table +
                     ", local: " + ttl_table,
                     ErrorCodes::METADATA_MISMATCH);
     }
 
+    if (ttl_move != from_zk.ttl_move)
+    {
+        if (allow_alter)
+        {
+            diff.ttl_move_changed = true;
+            diff.new_ttl_move = from_zk.ttl_move;
+        }
+        else
+            throw Exception(
+                    "Existing table metadata in ZooKeeper differs in move TTL."
+                    " Stored in ZooKeeper: " + from_zk.ttl_move +
+                    ", local: " + ttl_move,
+                    ErrorCodes::METADATA_MISMATCH);
+    }
+
     if (skip_indices != from_zk.skip_indices)
     {
         if (allow_alter)

dbms/src/Storages/MergeTree/ReplicatedMergeTreeTableMetadata.h

@@ -28,6 +28,7 @@ struct ReplicatedMergeTreeTableMetadata
     String skip_indices;
     String constraints;
     String ttl_table;
+    String ttl_move;
     UInt64 index_granularity_bytes;
 
     ReplicatedMergeTreeTableMetadata() = default;
@@ -53,9 +54,12 @@ struct ReplicatedMergeTreeTableMetadata
         bool ttl_table_changed = false;
         String new_ttl_table;
 
+        bool ttl_move_changed = false;
+        String new_ttl_move;
+
         bool empty() const
         {
-            return !sorting_key_changed && !skip_indices_changed && !ttl_table_changed && !constraints_changed;
+            return !sorting_key_changed && !skip_indices_changed && !ttl_table_changed && !constraints_changed && !ttl_move_changed;
         }
     };
 

dbms/src/Storages/PartitionCommands.cpp

@@ -1,5 +1,6 @@
 #include <Storages/PartitionCommands.h>
 #include <Storages/IStorage.h>
+#include <Storages/MergeTree/PartDestinationType.h>
 #include <Parsers/ASTAlterQuery.h>
 #include <Parsers/ASTIdentifier.h>
 
@@ -47,12 +48,14 @@ std::optional<PartitionCommand> PartitionCommand::parse(const ASTAlterCommand *
         res.part = command_ast->part;
         switch (command_ast->move_destination_type)
         {
-            case ASTAlterCommand::MoveDestinationType::DISK:
+            case PartDestinationType::DISK:
                 res.move_destination_type = PartitionCommand::MoveDestinationType::DISK;
                 break;
-            case ASTAlterCommand::MoveDestinationType::VOLUME:
+            case PartDestinationType::VOLUME:
                 res.move_destination_type = PartitionCommand::MoveDestinationType::VOLUME;
                 break;
+            default:
+                break;
         }
         res.move_destination_name = command_ast->move_destination_name;
         return res;

dbms/src/Storages/StorageMergeTree.cpp

@@ -350,9 +350,15 @@ public:
 
         /// if we mutate part, than we should reserve space on the same disk, because mutations possible can create hardlinks
         if (is_mutation)
-            reserved_space = future_part_.parts[0]->disk->reserve(total_size);
+            reserved_space = storage.tryReserveSpace(total_size, future_part_.parts[0]->disk);
         else
-            reserved_space = storage.reserveSpace(total_size);
+        {
+            MergeTreeDataPart::TTLInfos ttl_infos;
+            for (auto & part_ptr : future_part_.parts)
+                ttl_infos.update(part_ptr->ttl_infos);
+
+            reserved_space = storage.tryReserveSpacePreferringTTLRules(total_size, ttl_infos, time(nullptr));
+        }
         if (!reserved_space)
         {
             if (is_mutation)