ClickHouse/dbms/src/Core/BlockInfo.h
2017-05-09 15:07:35 -04:00

47 lines
1.3 KiB
C++

#pragma once
#include <Core/Types.h>
namespace DB
{
class ReadBuffer;
class WriteBuffer;
/** More information about the block.
*/
struct BlockInfo
{
/** is_overflows:
* After running GROUP BY ... WITH TOTALS with the max_rows_to_group_by and group_by_overflow_mode = 'any' settings,
* a row is inserted in the separate block with aggregated values that have not passed max_rows_to_group_by.
* If it is such a block, then is_overflows is set to true for it.
*/
/** bucket_num:
* When using the two-level aggregation method, data with different key groups are scattered across different buckets.
* In this case, the bucket number is indicated here. It is used to optimize the merge for distributed aggregation.
* Otherwise -1.
*/
#define APPLY_FOR_BLOCK_INFO_FIELDS(M) \
M(bool, is_overflows, false, 1) \
M(Int32, bucket_num, -1, 2)
#define DECLARE_FIELD(TYPE, NAME, DEFAULT, FIELD_NUM) \
TYPE NAME = DEFAULT;
APPLY_FOR_BLOCK_INFO_FIELDS(DECLARE_FIELD)
#undef DECLARE_FIELD
/// Write the values in binary form. NOTE: You could use protobuf, but it would be overkill for this case.
void write(WriteBuffer & out) const;
/// Read the values in binary form.
void read(ReadBuffer & in);
};
}