ClickHouse/src/Functions/normalizedQueryHash.cpp

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#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypesNumber.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnsNumber.h>
#include <Functions/FunctionFactory.h>
#include <Parsers/queryNormalization.h>
#include <common/find_symbols.h>
#include <Common/StringUtils/StringUtils.h>
#include <Common/SipHash.h>
/** The function returns 64bit hash value that is identical for similar queries.
* See also 'normalizeQuery'. This function is only slightly more efficient.
*/
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
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extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
template <bool keep_names>
struct Impl
{
static void vector(
const ColumnString::Chars & data,
const ColumnString::Offsets & offsets,
PaddedPODArray<UInt64> & res_data)
{
size_t size = offsets.size();
res_data.resize(size);
ColumnString::Offset prev_src_offset = 0;
for (size_t i = 0; i < size; ++i)
{
ColumnString::Offset curr_src_offset = offsets[i];
res_data[i] = normalizedQueryHash<keep_names>(
reinterpret_cast<const char *>(&data[prev_src_offset]), reinterpret_cast<const char *>(&data[curr_src_offset - 1]));
prev_src_offset = offsets[i];
}
}
};
template <bool keep_names>
class FunctionNormalizedQueryHash : public IFunction
{
public:
static constexpr auto name = keep_names ? "normalizedQueryHashKeepNames" : "normalizedQueryHash";
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static FunctionPtr create(ContextPtr)
{
return std::make_shared<FunctionNormalizedQueryHash>();
}
String getName() const override
{
return name;
}
size_t getNumberOfArguments() const override
{
return 1;
}
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
if (!isString(arguments[0]))
throw Exception("Illegal type " + arguments[0]->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeUInt64>();
}
bool useDefaultImplementationForConstants() const override { return true; }
bool isSuitableForShortCircuitArgumentsExecution() const override { return true; }
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t /*input_rows_count*/) const override
{
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const ColumnPtr column = arguments[0].column;
if (const ColumnString * col = checkAndGetColumn<ColumnString>(column.get()))
{
auto col_res = ColumnUInt64::create();
typename ColumnUInt64::Container & vec_res = col_res->getData();
vec_res.resize(col->size());
Impl<keep_names>::vector(col->getChars(), col->getOffsets(), vec_res);
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return col_res;
}
else
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throw Exception("Illegal column " + arguments[0].column->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
}
void registerFunctionNormalizedQueryHash(FunctionFactory & factory)
{
factory.registerFunction<FunctionNormalizedQueryHash<true>>();
factory.registerFunction<FunctionNormalizedQueryHash<false>>();
}
}