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#pragma once
#include <Core/Block.h>
#include <Core/SortDescription.h>
namespace DB
{
/// Sort one block by `description`. If limit != 0, then the partial sort of the first `limit` rows is produced.
void sortBlock(Block & block, const SortDescription & description, UInt64 limit = 0);
/** Same as sortBlock, but do not sort the block, but only calculate the permutation of the values,
* so that you can rearrange the column values yourself.
* Sorting is stable. This is important for keeping the order of rows in the CollapsingMergeTree engine
* - because based on the order of rows it is determined whether to delete or leave groups of rows when collapsing.
* Used only in StorageMergeTree to sort the data with INSERT.
*/
void stableGetPermutation(const Block & block, const SortDescription & description, IColumn::Permutation & out_permutation);
/** Quickly check whether the block is already sorted. If the block is not sorted - returns false as fast as possible.
*/
bool isAlreadySorted(const Block & block, const SortDescription & description);
}
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