ClickHouse/dbms/include/DB/Dictionaries/MySQLBlockInputStream.h

147 lines
4.7 KiB
C++

#pragma once
#include <DB/Core/Block.h>
#include <DB/DataStreams/IProfilingBlockInputStream.h>
#include <DB/DataTypes/DataTypesNumberFixed.h>
#include <DB/DataTypes/DataTypeString.h>
#include <DB/DataTypes/DataTypeDate.h>
#include <DB/DataTypes/DataTypeDateTime.h>
#include <statdaemons/ext/range.hpp>
#include <mysqlxx/Query.h>
#include <vector>
#include <string>
namespace DB
{
/// Allows processing results of a MySQL query as a sequence of Blocks, simplifies chaining
class MySQLBlockInputStream final : public IProfilingBlockInputStream
{
enum struct value_type_t
{
UInt8,
UInt16,
UInt32,
UInt64,
Int8,
Int16,
Int32,
Int64,
Float32,
Float64,
String,
Date,
DateTime
};
public:
MySQLBlockInputStream(const mysqlxx::PoolWithFailover::Entry & entry,
const std::string & query_str,
const Block & sample_block,
const std::size_t max_block_size)
: entry{entry}, query{this->entry->query(query_str)}, result{query.use()},
sample_block{sample_block}, max_block_size{max_block_size}
{
types.reserve(sample_block.columns());
for (const auto idx : ext::range(0, sample_block.columns()))
{
const auto type = sample_block.getByPosition(idx).type.get();
if (typeid_cast<const DataTypeUInt8 *>(type))
types.push_back(value_type_t::UInt8);
else if (typeid_cast<const DataTypeUInt16 *>(type))
types.push_back(value_type_t::UInt16);
else if (typeid_cast<const DataTypeUInt32 *>(type))
types.push_back(value_type_t::UInt32);
else if (typeid_cast<const DataTypeUInt64 *>(type))
types.push_back(value_type_t::UInt64);
else if (typeid_cast<const DataTypeInt8 *>(type))
types.push_back(value_type_t::Int8);
else if (typeid_cast<const DataTypeInt16 *>(type))
types.push_back(value_type_t::Int16);
else if (typeid_cast<const DataTypeInt32 *>(type))
types.push_back(value_type_t::Int32);
else if (typeid_cast<const DataTypeInt64 *>(type))
types.push_back(value_type_t::Int64);
else if (typeid_cast<const DataTypeFloat32 *>(type))
types.push_back(value_type_t::Float32);
else if (typeid_cast<const DataTypeInt64 *>(type))
types.push_back(value_type_t::Float64);
else if (typeid_cast<const DataTypeString *>(type))
types.push_back(value_type_t::String);
else if (typeid_cast<const DataTypeDate *>(type))
types.push_back(value_type_t::Date);
else if (typeid_cast<const DataTypeDateTime *>(type))
types.push_back(value_type_t::DateTime);
else
throw Exception{
"Unsupported type " + type->getName(),
ErrorCodes::UNKNOWN_TYPE
};
}
}
String getName() const override { return "MySQLBlockInputStream"; }
String getID() const override
{
return "MySQL(" + query.str() + ")";
}
private:
Block readImpl() override
{
auto block = sample_block.cloneEmpty();
if (block.columns() != result.getNumFields())
throw Exception{
"mysqlxx::UseQueryResult contains " + toString(result.getNumFields()) + " columns while " +
toString(block.columns()) + " expected",
ErrorCodes::NUMBER_OF_COLUMNS_DOESNT_MATCH
};
std::size_t rows = 0;
while (auto row = result.fetch())
{
/// @todo cache pointers returned by the calls to getByPosition
for (const auto idx : ext::range(0, row.size()))
insertValue(block.getByPosition(idx).column, row[idx], types[idx]);
++rows;
if (rows == max_block_size)
break;
}
return rows == 0 ? Block{} : block;
};
static void insertValue(ColumnPtr & column, const mysqlxx::Value & value, const value_type_t type)
{
switch (type)
{
case value_type_t::UInt8: column->insert(static_cast<UInt64>(value)); break;
case value_type_t::UInt16: column->insert(static_cast<UInt64>(value)); break;
case value_type_t::UInt32: column->insert(static_cast<UInt64>(value)); break;
case value_type_t::UInt64: column->insert(static_cast<UInt64>(value)); break;
case value_type_t::Int8: column->insert(static_cast<Int64>(value)); break;
case value_type_t::Int16: column->insert(static_cast<Int64>(value)); break;
case value_type_t::Int32: column->insert(static_cast<Int64>(value)); break;
case value_type_t::Int64: column->insert(static_cast<Int64>(value)); break;
case value_type_t::Float32: column->insert(static_cast<Float64>(value)); break;
case value_type_t::Float64: column->insert(static_cast<Float64>(value)); break;
case value_type_t::String: column->insert(value.getString()); break;
case value_type_t::Date: column->insert(static_cast<UInt64>(UInt16{value.getDate().getDayNum()})); break;
case value_type_t::DateTime: column->insert(static_cast<UInt64>(time_t{value.getDateTime()})); break;
};
}
mysqlxx::PoolWithFailover::Entry entry;
mysqlxx::Query query;
mysqlxx::UseQueryResult result;
Block sample_block;
const std::size_t max_block_size;
std::vector<value_type_t> types;
};
}