Updated implementation

src/DataTypes/Utils.cpp

@@ -0,0 +1,231 @@
+#include <DataTypes/Utils.h>
+#include <DataTypes/DataTypesDecimal.h>
+#include <DataTypes/DataTypeNullable.h>
+#include <DataTypes/DataTypeLowCardinality.h>
+#include <DataTypes/DataTypeArray.h>
+#include <DataTypes/DataTypeMap.h>
+#include <DataTypes/DataTypeTuple.h>
+
+namespace DB
+{
+
+bool canBeSafelyCasted(const DataTypePtr & from_type, const DataTypePtr & to_type)
+{
+    auto from_which_type = WhichDataType(from_type->getTypeId());
+    bool to_type_was_nullable = isNullableOrLowCardinalityNullable(to_type);
+    auto to_type_unwrapped = removeNullable(removeLowCardinality(to_type));
+
+    if (from_type->equals(*to_type))
+        return true;
+
+    auto to_which_type = WhichDataType(to_type->getTypeId());
+
+    switch (from_which_type.idx)
+    {
+        case TypeIndex::UInt8:
+        case TypeIndex::UInt16:
+        case TypeIndex::UInt32:
+        case TypeIndex::UInt64:
+        case TypeIndex::UInt128:
+        case TypeIndex::UInt256:
+        {
+            if (to_which_type.isUInt() &&
+                to_type_unwrapped->getSizeOfValueInMemory() >= from_type->getSizeOfValueInMemory())
+                return true;
+
+            if (to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::Int8:
+        case TypeIndex::Int16:
+        case TypeIndex::Int32:
+        case TypeIndex::Int64:
+        case TypeIndex::Int128:
+        case TypeIndex::Int256:
+        {
+            if (to_which_type.isInt() &&
+                to_type_unwrapped->getSizeOfValueInMemory() >= from_type->getSizeOfValueInMemory())
+                return true;
+
+            if (to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::Float32:
+        {
+            if (to_which_type.isFloat64() || to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::Float64:
+        case TypeIndex::Date:
+        case TypeIndex::Date32:
+        case TypeIndex::DateTime:
+        case TypeIndex::DateTime64:
+        case TypeIndex::FixedString:
+        case TypeIndex::Enum8:
+        case TypeIndex::Enum16:
+        case TypeIndex::IPv6:
+        {
+            if (to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::Decimal32:
+        case TypeIndex::Decimal64:
+        case TypeIndex::Decimal128:
+        case TypeIndex::Decimal256:
+        {
+            if (to_which_type.isDecimal())
+            {
+                auto from_type_decimal_precision = getDecimalPrecision(*from_type);
+                auto to_type_decimal_precision = getDecimalPrecision(*to_type_unwrapped);
+                if (from_type_decimal_precision > to_type_decimal_precision)
+                    return false;
+
+                auto from_type_decimal_scale = getDecimalScale(*from_type);
+                auto to_type_decimal_scale = getDecimalScale(*to_type_unwrapped);
+                if (from_type_decimal_scale > to_type_decimal_scale)
+                    return false;
+
+                return true;
+            }
+
+            if (to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::UUID:
+        {
+            if (to_which_type.isUInt128() || to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::IPv4:
+        {
+            if (to_which_type.isUInt32() || to_which_type.isUInt64() || to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::Nullable:
+        {
+            if (to_type_was_nullable)
+            {
+                const auto & from_type_nullable = assert_cast<const DataTypeNullable &>(*from_type);
+                return canBeSafelyCasted(from_type_nullable.getNestedType(), to_type_unwrapped);
+            }
+
+            if (to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::LowCardinality:
+        {
+            const auto & from_type_low_cardinality = assert_cast<const DataTypeLowCardinality &>(*from_type);
+            return canBeSafelyCasted(from_type_low_cardinality.getDictionaryType(), to_type_unwrapped);
+        }
+        case TypeIndex::Array:
+        {
+            if (to_which_type.isArray())
+            {
+                const auto & from_type_array = assert_cast<const DataTypeArray &>(*from_type);
+                const auto & to_type_array = assert_cast<const DataTypeArray &>(*to_type_unwrapped);
+                return canBeSafelyCasted(from_type_array.getNestedType(), to_type_array.getNestedType());
+            }
+
+            if (to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::Map:
+        {
+            if (to_which_type.isMap())
+            {
+                const auto & from_type_map = assert_cast<const DataTypeMap &>(*from_type);
+                const auto & to_type_map = assert_cast<const DataTypeMap &>(*to_type_unwrapped);
+                if (!canBeSafelyCasted(from_type_map.getKeyType(), to_type_map.getKeyType()))
+                    return false;
+
+                if (!canBeSafelyCasted(from_type_map.getValueType(), to_type_map.getValueType()))
+                    return false;
+
+                return true;
+            }
+
+            if (to_which_type.isArray())
+            {
+                // Map nested type is Array(Tuple(key_type, value_type))
+                const auto & from_type_map = assert_cast<const DataTypeMap &>(*from_type);
+                const auto & to_type_array = assert_cast<const DataTypeArray &>(*to_type_unwrapped);
+                const auto * to_type_nested_tuple_type = typeid_cast<const DataTypeTuple *>(to_type_array.getNestedType().get());
+                if (!to_type_nested_tuple_type)
+                    return false;
+
+                const auto & to_type_tuple_elements = to_type_nested_tuple_type->getElements();
+                if (to_type_tuple_elements.size() != 2)
+                    return false;
+
+                if (!canBeSafelyCasted(from_type_map.getKeyType(), to_type_tuple_elements[0]))
+                    return false;
+
+                if (!canBeSafelyCasted(from_type_map.getValueType(), to_type_tuple_elements[1]))
+                    return false;
+
+                return true;
+            }
+
+            if (to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::Tuple:
+        {
+            if (to_which_type.isTuple())
+            {
+                const auto & from_type_tuple = assert_cast<const DataTypeTuple &>(*from_type);
+                const auto & to_type_tuple = assert_cast<const DataTypeTuple &>(*to_type_unwrapped);
+
+                const auto & from_tuple_type_elements = from_type_tuple.getElements();
+                const auto & to_tuple_type_elements = to_type_tuple.getElements();
+
+                size_t lhs_type_elements_size = from_tuple_type_elements.size();
+                if (lhs_type_elements_size != to_tuple_type_elements.size())
+                    return false;
+
+                for (size_t i = 0; i < lhs_type_elements_size; ++i)
+                    if (!canBeSafelyCasted(from_tuple_type_elements[i], to_tuple_type_elements[i]))
+                        return false;
+
+                return true;
+            }
+
+            if (to_which_type.isString())
+                return true;
+
+            return false;
+        }
+        case TypeIndex::String:
+        case TypeIndex::Object:
+        case TypeIndex::Set:
+        case TypeIndex::Interval:
+        case TypeIndex::Function:
+        case TypeIndex::AggregateFunction:
+        case TypeIndex::Nothing:
+            return false;
+    }
+
+    return true;
+}
+
+}

src/DataTypes/Utils.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <DataTypes/IDataType.h>
+
+namespace DB
+{
+
+/** Returns true if from_type can be safely casted to to_type.
+  *
+  * Examples:
+  * From type UInt8 to type UInt16 returns true.
+  * From type UInt16 to type UInt8 returns false.
+  * From type String to type LowCardinality(String) returns true.
+  * From type LowCardinality(String) to type String returns true.
+  * From type String to type UInt8 returns false.
+  */
+bool canBeSafelyCasted(const DataTypePtr & from_type, const DataTypePtr & to_type);
+
+}

src/Functions/FunctionHelpers.cpp

@@ -6,7 +6,6 @@
 #include <Columns/ColumnNullable.h>
 #include <Columns/ColumnLowCardinality.h>
 #include <Common/assert_cast.h>
-#include <DataTypes/DataTypeNullable.h>
 
 
 namespace DB

src/Storages/MergeTree/KeyCondition.cpp

@@ -3,6 +3,7 @@
 #include <DataTypes/DataTypesNumber.h>
 #include <DataTypes/FieldToDataType.h>
 #include <DataTypes/getLeastSupertype.h>
+#include <DataTypes/Utils.h>
 #include <Interpreters/TreeRewriter.h>
 #include <Interpreters/ExpressionAnalyzer.h>
 #include <Interpreters/ExpressionActions.h>
@@ -1257,7 +1258,7 @@ bool KeyCondition::tryPrepareSetIndex(
     if (!future_set)
         return false;
 
-    const auto & set_types = future_set->getTypes();
+    const auto set_types = future_set->getTypes();
     size_t set_types_size = set_types.size();
     size_t indexes_mapping_size = indexes_mapping.size();
 
@@ -1283,24 +1284,37 @@ bool KeyCondition::tryPrepareSetIndex(
 
     for (size_t indexes_mapping_index = 0; indexes_mapping_index < indexes_mapping_size; ++indexes_mapping_index)
     {
+        const auto & key_column_type = data_types[indexes_mapping_index];
         size_t set_element_index = indexes_mapping[indexes_mapping_index].tuple_index;
-        const auto & set_element_type = set_types[set_element_index];
+        auto set_element_type = set_types[set_element_index];
-        auto & set_column = set_columns[set_element_index];
+        auto set_column = set_columns[set_element_index];
 
-        bool is_set_column_nullable = set_element_type->isNullable();
+        if (canBeSafelyCasted(set_element_type, key_column_type))
-        bool is_set_column_low_cardinality_nullable = set_element_type->isLowCardinalityNullable();
+        {
+            set_columns[set_element_index] = castColumn({set_column, set_element_type, {}}, key_column_type);
+            continue;
+        }
+
+        if (!key_column_type->canBeInsideNullable())
+            return false;
 
         const NullMap * set_column_null_map = nullptr;
 
-        if (is_set_column_nullable || is_set_column_low_cardinality_nullable)
+        if (isNullableOrLowCardinalityNullable(set_element_type))
         {
-            if (is_set_column_low_cardinality_nullable)
+            if (WhichDataType(set_element_type).isLowCardinality())
+            {
+                set_element_type = removeLowCardinality(set_element_type);
                 set_column = set_column->convertToFullColumnIfLowCardinality();
-
-            set_column_null_map = &assert_cast<const ColumnNullable &>(*set_column).getNullMapData();
             }
 
-        auto nullable_set_column = castColumnAccurateOrNull({set_column, set_element_type, {}}, data_types[indexes_mapping_index]);
+            set_element_type = removeNullable(set_element_type);
+            const auto & set_column_nullable = assert_cast<const ColumnNullable &>(*set_column);
+            set_column_null_map = &set_column_nullable.getNullMapData();
+            set_column = set_column_nullable.getNestedColumnPtr();
+        }
+
+        auto nullable_set_column = castColumnAccurateOrNull({set_column, set_element_type, {}}, key_column_type);
         const auto & nullable_set_column_typed = assert_cast<const ColumnNullable &>(*nullable_set_column);
         const auto & nullable_set_column_null_map = nullable_set_column_typed.getNullMapData();
         size_t nullable_set_column_null_map_size = nullable_set_column_null_map.size();
@@ -1321,6 +1335,8 @@ bool KeyCondition::tryPrepareSetIndex(
 
             set_column = nullable_set_column_typed.getNestedColumn().filter(filter, 0);
         }
+
+        set_columns[set_element_index] = std::move(set_column);
     }
 
     out.set_index = std::make_shared<MergeTreeSetIndex>(set_columns, std::move(indexes_mapping));