ClickHouse/dbms/src/Formats/MySQLBlockInputStream.cpp
2019-02-15 14:46:07 +03:00

136 lines
4.7 KiB
C++

#include <Common/config.h>
#if USE_MYSQL
# include <vector>
# include <Columns/ColumnNullable.h>
# include <Columns/ColumnString.h>
# include <Columns/ColumnsNumber.h>
# include <IO/ReadHelpers.h>
# include <IO/WriteHelpers.h>
# include <ext/range.h>
# include "MySQLBlockInputStream.h"
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_COLUMNS_DOESNT_MATCH;
}
MySQLBlockInputStream::MySQLBlockInputStream(
const mysqlxx::PoolWithFailover::Entry & entry, const std::string & query_str, const Block & sample_block, const UInt64 max_block_size)
: entry{entry}, query{this->entry->query(query_str)}, result{query.use()}, max_block_size{max_block_size}
{
if (sample_block.columns() != result.getNumFields())
throw Exception{"mysqlxx::UseQueryResult contains " + toString(result.getNumFields()) + " columns while "
+ toString(sample_block.columns()) + " expected",
ErrorCodes::NUMBER_OF_COLUMNS_DOESNT_MATCH};
description.init(sample_block);
}
namespace
{
using ValueType = ExternalResultDescription::ValueType;
void insertValue(IColumn & column, const ValueType type, const mysqlxx::Value & value)
{
switch (type)
{
case ValueType::UInt8:
static_cast<ColumnUInt8 &>(column).insertValue(value.getUInt());
break;
case ValueType::UInt16:
static_cast<ColumnUInt16 &>(column).insertValue(value.getUInt());
break;
case ValueType::UInt32:
static_cast<ColumnUInt32 &>(column).insertValue(value.getUInt());
break;
case ValueType::UInt64:
static_cast<ColumnUInt64 &>(column).insertValue(value.getUInt());
break;
case ValueType::Int8:
static_cast<ColumnInt8 &>(column).insertValue(value.getInt());
break;
case ValueType::Int16:
static_cast<ColumnInt16 &>(column).insertValue(value.getInt());
break;
case ValueType::Int32:
static_cast<ColumnInt32 &>(column).insertValue(value.getInt());
break;
case ValueType::Int64:
static_cast<ColumnInt64 &>(column).insertValue(value.getInt());
break;
case ValueType::Float32:
static_cast<ColumnFloat32 &>(column).insertValue(value.getDouble());
break;
case ValueType::Float64:
static_cast<ColumnFloat64 &>(column).insertValue(value.getDouble());
break;
case ValueType::String:
static_cast<ColumnString &>(column).insertData(value.data(), value.size());
break;
case ValueType::Date:
static_cast<ColumnUInt16 &>(column).insertValue(UInt16(value.getDate().getDayNum()));
break;
case ValueType::DateTime:
static_cast<ColumnUInt32 &>(column).insertValue(UInt32(value.getDateTime()));
break;
case ValueType::UUID:
static_cast<ColumnUInt128 &>(column).insert(parse<UUID>(value.data(), value.size()));
break;
}
}
void insertDefaultValue(IColumn & column, const IColumn & sample_column) { column.insertFrom(sample_column, 0); }
}
Block MySQLBlockInputStream::readImpl()
{
auto row = result.fetch();
if (!row)
return {};
MutableColumns columns(description.sample_block.columns());
for (const auto i : ext::range(0, columns.size()))
columns[i] = description.sample_block.getByPosition(i).column->cloneEmpty();
size_t num_rows = 0;
while (row)
{
for (const auto idx : ext::range(0, row.size()))
{
const auto value = row[idx];
if (!value.isNull())
{
if (description.types[idx].second)
{
ColumnNullable & column_nullable = static_cast<ColumnNullable &>(*columns[idx]);
insertValue(column_nullable.getNestedColumn(), description.types[idx].first, value);
column_nullable.getNullMapData().emplace_back(0);
}
else
insertValue(*columns[idx], description.types[idx].first, value);
}
else
insertDefaultValue(*columns[idx], *description.sample_block.getByPosition(idx).column);
}
++num_rows;
if (num_rows == max_block_size)
break;
row = result.fetch();
}
return description.sample_block.cloneWithColumns(std::move(columns));
}
}
#endif