Merge pull request #54613 from bigo-sg/improve_json_query

Improve json sql functions by serializing json element into column's buffer direclty

src/Common/JSONParsers/SimdJSONParser.h

@@ -8,6 +8,9 @@
 #    include <base/defines.h>
 #    include <simdjson.h>
 #    include "ElementTypes.h"
+#    include <Common/PODArray_fwd.h>
+#    include <Common/PODArray.h>
+#    include <charconv>
 
 namespace DB
 {
@@ -16,6 +19,254 @@ namespace ErrorCodes
     extern const int CANNOT_ALLOCATE_MEMORY;
 }
 
+/// Format elements of basic types into string.
+/// The original implementation is mini_formatter in simdjson.h. But it is not public API, so we
+/// add a implementation here.
+class SimdJSONBasicFormatter
+{
+public:
+    explicit SimdJSONBasicFormatter(PaddedPODArray<UInt8> & buffer_) : buffer(buffer_) {}
+    inline void comma() { oneChar(','); }
+    /** Start an array, prints [ **/
+    inline void startArray() { oneChar('['); }
+    /** End an array, prints ] **/
+    inline void endArray() { oneChar(']'); }
+    /** Start an array, prints { **/
+    inline void startObject() { oneChar('{'); }
+    /** Start an array, prints } **/
+    inline void endObject() { oneChar('}'); }
+    /** Prints a true **/
+    inline void trueAtom()
+    {
+        const char * s = "true";
+        buffer.insert(s, s + 4);
+    }
+    /** Prints a false **/
+    inline void falseAtom()
+    {
+        const char * s = "false";
+        buffer.insert(s, s + 5);
+    }
+    /** Prints a null **/
+    inline void nullAtom()
+    {
+        const char * s = "null";
+        buffer.insert(s, s + 4);
+    }
+    /** Prints a number **/
+    inline void number(int64_t x)
+    {
+        char number_buffer[24];
+        auto res = std::to_chars(number_buffer, number_buffer + sizeof(number_buffer), x);
+        buffer.insert(number_buffer, res.ptr);
+    }
+    /** Prints a number **/
+    inline void number(uint64_t x)
+    {
+        char number_buffer[24];
+        auto res = std::to_chars(number_buffer, number_buffer + sizeof(number_buffer), x);
+        buffer.insert(number_buffer, res.ptr);
+    }
+    /** Prints a number **/
+    inline void number(double x)
+    {
+        char number_buffer[24];
+        auto res = std::to_chars(number_buffer, number_buffer + sizeof(number_buffer), x);
+        buffer.insert(number_buffer, res.ptr);
+    }
+    /** Prints a key (string + colon) **/
+    inline void key(std::string_view unescaped)
+    {
+        string(unescaped);
+        oneChar(':');
+    }
+    /** Prints a string. The string is escaped as needed. **/
+    inline void string(std::string_view unescaped)
+    {
+        oneChar('\"');
+        size_t i = 0;
+        // Fast path for the case where we have no control character, no ", and no backslash.
+        // This should include most keys.
+        //
+        // We would like to use 'bool' but some compilers take offense to bitwise operation
+        // with bool types.
+        constexpr static char needs_escaping[] = {
+            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+        for (; i + 8 <= unescaped.length(); i += 8)
+        {
+            // Poor's man vectorization. This could get much faster if we used SIMD.
+            //
+            // It is not the case that replacing '|' with '||' would be neutral performance-wise.
+            if (needs_escaping[uint8_t(unescaped[i])] | needs_escaping[uint8_t(unescaped[i + 1])]
+                | needs_escaping[uint8_t(unescaped[i + 2])] | needs_escaping[uint8_t(unescaped[i + 3])]
+                | needs_escaping[uint8_t(unescaped[i + 4])] | needs_escaping[uint8_t(unescaped[i + 5])]
+                | needs_escaping[uint8_t(unescaped[i + 6])] | needs_escaping[uint8_t(unescaped[i + 7])])
+            {
+                break;
+            }
+        }
+        for (; i < unescaped.length(); i++)
+        {
+            if (needs_escaping[uint8_t(unescaped[i])])
+            {
+                break;
+            }
+        }
+        // The following is also possible and omits a 256-byte table, but it is slower:
+        // for (; (i < unescaped.length()) && (uint8_t(unescaped[i]) > 0x1F)
+        //      && (unescaped[i] != '\"') && (unescaped[i] != '\\'); i++) {}
+
+        // At least for long strings, the following should be fast. We could
+        // do better by integrating the checks and the insertion.
+        buffer.insert(unescaped.data(), unescaped.data() + i);
+        // We caught a control character if we enter this loop (slow).
+        // Note that we are do not restart from the beginning, but rather we continue
+        // from the point where we encountered something that requires escaping.
+        for (; i < unescaped.length(); i++)
+        {
+            switch (unescaped[i])
+            {
+                case '\"': {
+                    const char * s = "\\\"";
+                    buffer.insert(s, s + 2);
+                }
+                break;
+                case '\\': {
+                    const char * s = "\\\\";
+                    buffer.insert(s, s + 2);
+                }
+                break;
+                default:
+                    if (uint8_t(unescaped[i]) <= 0x1F)
+                    {
+                        // If packed, this uses 8 * 32 bytes.
+                        // Note that we expect most compilers to embed this code in the data
+                        // section.
+                        constexpr static simdjson::escape_sequence escaped[32] = {
+                            {6, "\\u0000"}, {6, "\\u0001"}, {6, "\\u0002"}, {6, "\\u0003"}, {6, "\\u0004"}, {6, "\\u0005"}, {6, "\\u0006"},
+                            {6, "\\u0007"}, {2, "\\b"},     {2, "\\t"},     {2, "\\n"},     {6, "\\u000b"}, {2, "\\f"},     {2, "\\r"},
+                            {6, "\\u000e"}, {6, "\\u000f"}, {6, "\\u0010"}, {6, "\\u0011"}, {6, "\\u0012"}, {6, "\\u0013"}, {6, "\\u0014"},
+                            {6, "\\u0015"}, {6, "\\u0016"}, {6, "\\u0017"}, {6, "\\u0018"}, {6, "\\u0019"}, {6, "\\u001a"}, {6, "\\u001b"},
+                            {6, "\\u001c"}, {6, "\\u001d"}, {6, "\\u001e"}, {6, "\\u001f"}};
+                        auto u = escaped[uint8_t(unescaped[i])];
+                        buffer.insert(u.string, u.string + u.length);
+                    }
+                    else
+                    {
+                        oneChar(unescaped[i]);
+                    }
+            } // switch
+        } // for
+        oneChar('\"');
+    }
+
+    inline void oneChar(char c)
+    {
+        buffer.push_back(c);
+    }
+private:
+    PaddedPODArray<UInt8> & buffer;
+
+};
+
+
+/// Format object elements into string, element, array, object, kv-pair.
+/// Similar to string_builder in simdjson.h.
+class SimdJSONElementFormatter
+{
+public:
+    explicit SimdJSONElementFormatter(PaddedPODArray<UInt8> & buffer_) : format(buffer_) {}
+    /** Append an element to the builder (to be printed) **/
+    inline void append(simdjson::dom::element value)
+    {
+        switch (value.type())
+        {
+            case simdjson::dom::element_type::UINT64: {
+                format.number(value.get_uint64().value_unsafe());
+                break;
+            }
+            case simdjson::dom::element_type::INT64: {
+                format.number(value.get_int64().value_unsafe());
+                break;
+            }
+            case simdjson::dom::element_type::DOUBLE: {
+                format.number(value.get_double().value_unsafe());
+                break;
+            }
+            case simdjson::dom::element_type::STRING: {
+                format.string(value.get_string().value_unsafe());
+                break;
+            }
+            case simdjson::dom::element_type::BOOL: {
+                if (value.get_bool().value_unsafe())
+                    format.trueAtom();
+                else
+                    format.falseAtom();
+                break;
+            }
+            case simdjson::dom::element_type::NULL_VALUE: {
+                format.nullAtom();
+                break;
+            }
+            case simdjson::dom::element_type::ARRAY: {
+                append(value.get_array().value_unsafe());
+                break;
+            }
+            case simdjson::dom::element_type::OBJECT: {
+                append(value.get_object().value_unsafe());
+                break;
+            }
+        }
+    }
+    /** Append an array to the builder (to be printed) **/
+    inline void append(simdjson::dom::array value)
+    {
+        format.startArray();
+        auto iter = value.begin();
+        auto end = value.end();
+        if (iter != end)
+        {
+            append(*iter);
+            for (++iter; iter != end; ++iter)
+            {
+                format.comma();
+                append(*iter);
+            }
+        }
+        format.endArray();
+    }
+
+    inline void append(simdjson::dom::object value)
+    {
+        format.startObject();
+        auto pair = value.begin();
+        auto end = value.end();
+        if (pair != end)
+        {
+            append(*pair);
+            for (++pair; pair != end; ++pair)
+            {
+                format.comma();
+                append(*pair);
+            }
+        }
+        format.endObject();
+    }
+
+    inline void append(simdjson::dom::key_value_pair kv)
+    {
+        format.key(kv.key);
+        append(kv.value);
+    }
+private:
+    SimdJSONBasicFormatter format;
+};
+
 /// This class can be used as an argument for the template class FunctionJSON.
 /// It provides ability to parse JSONs using simdjson library.
 struct SimdJSONParser

src/Functions/FunctionSQLJSON.h

@@ -35,10 +35,92 @@ extern const int TOO_FEW_ARGUMENTS_FOR_FUNCTION;
 extern const int BAD_ARGUMENTS;
 }
 
+/// Have implemented the operator << for json elements. So we could use stringstream to serialize json elements.
+/// But stingstream have bad performance, not recommend to use it.
+template <typename Element>
+class DefaultJSONStringSerializer
+{
+public:
+    explicit DefaultJSONStringSerializer(ColumnString & col_str_) : col_str(col_str_) { }
+
+    inline void addRawData(const char * ptr, size_t len)
+    {
+        out << std::string_view(ptr, len);
+    }
+
+    inline void addRawString(std::string_view str)
+    {
+        out << str;
+    }
+
+    /// serialize the json element into stringstream
+    inline void addElement(const Element & element)
+    {
+        out << element.getElement();
+    }
+    inline void commit()
+    {
+        auto out_str = out.str();
+        col_str.insertData(out_str.data(), out_str.size());
+    }
+    inline void rollback() {}
+private:
+    ColumnString & col_str;
+    std::stringstream out; // STYLE_CHECK_ALLOW_STD_STRING_STREAM
+};
+
+/// A more efficient way to serialize json elements into destination column.
+/// Formatter takes the chars buffer in the ColumnString and put data into it directly.
+template<typename Element, typename Formatter>
+class JSONStringSerializer
+{
+public:
+    explicit JSONStringSerializer(ColumnString & col_str_)
+        : col_str(col_str_), chars(col_str_.getChars()), offsets(col_str_.getOffsets()), formatter(col_str_.getChars())
+    {
+        prev_offset = offsets.empty() ? 0 : offsets.back();
+    }
+    /// Put the data into column's buffer directly.
+    inline void addRawData(const char * ptr, size_t len)
+    {
+        chars.insert(ptr, ptr + len);
+    }
+
+    inline void addRawString(std::string_view str)
+    {
+        chars.insert(str.data(), str.data() + str.size());
+    }
+
+    /// serialize the json element into column's buffer directly
+    inline void addElement(const Element & element)
+    {
+        formatter.append(element.getElement());
+    }
+    inline void commit()
+    {
+        chars.push_back(0);
+        offsets.push_back(chars.size());
+    }
+    inline void rollback()
+    {
+        chars.resize(prev_offset);
+    }
+private:
+    ColumnString & col_str;
+    ColumnString::Chars & chars;
+    IColumn::Offsets & offsets;
+    Formatter formatter;
+    size_t prev_offset;
+
+};
+
+class EmptyJSONStringSerializer{};
+
+
 class FunctionSQLJSONHelpers
 {
 public:
-    template <typename Name, template <typename> typename Impl, class JSONParser>
+    template <typename Name, typename Impl, class JSONParser>
     class Executor
     {
     public:
@@ -116,7 +198,7 @@ public:
             bool document_ok = false;
 
             /// Parse JSON for every row
-            Impl<JSONParser> impl;
+            Impl impl;
             for (const auto i : collections::range(0, input_rows_count))
             {
                 std::string_view json{
@@ -138,7 +220,7 @@ public:
     };
 };
 
-template <typename Name, template <typename> typename Impl>
+template <typename Name, template <typename, typename> typename Impl>
 class FunctionSQLJSON : public IFunction, WithConstContext
 {
 public:
@@ -155,7 +237,8 @@ public:
 
     DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
     {
-        return Impl<DummyJSONParser>::getReturnType(Name::name, arguments, getContext());
+        return Impl<DummyJSONParser, DefaultJSONStringSerializer<DummyJSONParser::Element>>::getReturnType(
+            Name::name, arguments, getContext());
     }
 
     ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
@@ -168,9 +251,14 @@ public:
         unsigned parse_depth = static_cast<unsigned>(getContext()->getSettingsRef().max_parser_depth);
 #if USE_SIMDJSON
         if (getContext()->getSettingsRef().allow_simdjson)
-            return FunctionSQLJSONHelpers::Executor<Name, Impl, SimdJSONParser>::run(arguments, result_type, input_rows_count, parse_depth, getContext());
+            return FunctionSQLJSONHelpers::Executor<
+                Name,
+                Impl<SimdJSONParser, JSONStringSerializer<SimdJSONParser::Element, SimdJSONElementFormatter>>,
+                SimdJSONParser>::run(arguments, result_type, input_rows_count, parse_depth, getContext());
 #endif
-        return FunctionSQLJSONHelpers::Executor<Name, Impl, DummyJSONParser>::run(arguments, result_type, input_rows_count, parse_depth, getContext());
+        return FunctionSQLJSONHelpers::
+            Executor<Name, Impl<DummyJSONParser, DefaultJSONStringSerializer<DummyJSONParser::Element>>, DummyJSONParser>::run(
+                arguments, result_type, input_rows_count, parse_depth, getContext());
     }
 };
 
@@ -189,7 +277,7 @@ struct NameJSONQuery
     static constexpr auto name{"JSON_QUERY"};
 };
 
-template <typename JSONParser>
+template <typename JSONParser, typename JSONStringSerializer>
 class JSONExistsImpl
 {
 public:
@@ -228,7 +316,7 @@ public:
     }
 };
 
-template <typename JSONParser>
+template <typename JSONParser, typename JSONStringSerializer>
 class JSONValueImpl
 {
 public:
@@ -279,11 +367,7 @@ public:
 
         if (status == VisitorStatus::Exhausted)
             return false;
-
+        ColumnString * col_str = nullptr;
-        std::stringstream out; // STYLE_CHECK_ALLOW_STD_STRING_STREAM
-        out << current_element.getElement();
-        auto output_str = out.str();
-        ColumnString * col_str;
         if (isColumnNullable(dest))
         {
             ColumnNullable & col_null = assert_cast<ColumnNullable &>(dest);
@@ -294,20 +378,15 @@ public:
         {
             col_str = assert_cast<ColumnString *>(&dest);
         }
-        ColumnString::Chars & data = col_str->getChars();
+        JSONStringSerializer json_serializer(*col_str);
-        ColumnString::Offsets & offsets = col_str->getOffsets();
-
         if (current_element.isString())
         {
-            ReadBufferFromString buf(output_str);
+            auto str = current_element.getString();
-            readJSONStringInto(data, buf);
+            json_serializer.addRawString(str);
-            data.push_back(0);
-            offsets.push_back(data.size());
         }
         else
-        {
+            json_serializer.addElement(current_element);
-            col_str->insertData(output_str.data(), output_str.size());
+        json_serializer.commit();
-        }
         return true;
     }
 };
@@ -316,7 +395,7 @@ public:
  * Function to test jsonpath member access, will be removed in final PR
  * @tparam JSONParser parser
  */
-template <typename JSONParser>
+template <typename JSONParser, typename JSONStringSerializer>
 class JSONQueryImpl
 {
 public:
@@ -328,23 +407,27 @@ public:
 
     static bool insertResultToColumn(IColumn & dest, const Element & root, ASTPtr & query_ptr, const ContextPtr &)
     {
+        ColumnString & col_str = assert_cast<ColumnString &>(dest);
+
         GeneratorJSONPath<JSONParser> generator_json_path(query_ptr);
         Element current_element = root;
         VisitorStatus status;
-        std::stringstream out; // STYLE_CHECK_ALLOW_STD_STRING_STREAM
-        /// Create json array of results: [res1, res2, ...]
-        out << "[";
         bool success = false;
+        const char * array_begin = "[";
+        const char * array_end = "]";
+        const char * comma = ", ";
+        JSONStringSerializer json_serializer(col_str);
+        json_serializer.addRawData(array_begin, 1);
         while ((status = generator_json_path.getNextItem(current_element)) != VisitorStatus::Exhausted)
         {
             if (status == VisitorStatus::Ok)
             {
                 if (success)
                 {
-                    out << ", ";
+                    json_serializer.addRawData(comma, 2);
                 }
                 success = true;
-                out << current_element.getElement();
+                json_serializer.addElement(current_element);
             }
             else if (status == VisitorStatus::Error)
             {
@@ -354,14 +437,13 @@ public:
             }
             current_element = root;
         }
-        out << "]";
         if (!success)
         {
+            json_serializer.rollback();
             return false;
         }
-        ColumnString & col_str = assert_cast<ColumnString &>(dest);
+        json_serializer.addRawData(array_end, 1);
-        auto output_str = out.str();
+        json_serializer.commit();
-        col_str.insertData(output_str.data(), output_str.size());
         return true;
     }
 };

tests/performance/json_extract_simdjson.xml

@@ -33,4 +33,8 @@
     <query>SELECT 'simdjson-12', count() FROM zeros(5000000) WHERE NOT ignore(JSONExtractFloat(materialize({long_json}), 'fparam', 'nested_2', -2))</query>
     <query>SELECT 'simdjson-13', count() FROM zeros(5000000) WHERE NOT ignore(JSONExtractBool(materialize({long_json}), 'bparam'))</query>
 
+    <query>SELECT 'simdjson-14', count() FROM zeros(5000000) WHERE NOT ignore(JSON_VALUE(materialize({long_json}), '$.nparam'))</query>
+    <query>SELECT 'simdjson-15', count() FROM zeros(5000000) WHERE NOT ignore(JSON_QUERY(materialize({long_json}), '$.nparam'))</query>
+    <query>SELECT 'simdjson-16', count() FROM zeros(5000000) WHERE NOT ignore(JSON_VALUE(materialize({json}), '$.nparam'))</query>
+    <query>SELECT 'simdjson-17', count() FROM zeros(5000000) WHERE NOT ignore(JSON_QUERY(materialize({json}), '$.nparam'))</query>
 </test>