partition_pruning.h File Reference

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Functions
bool	prune_partitions (THD *thd, TABLE *table, Query_block *query_block, Item *pprune_cond)
	Perform partition pruning for a given table and condition. More...

Function Documentation

prune_partitions()

bool prune_partitions	(	THD *	thd,
		TABLE *	table,
		Query_block *	query_block,
		Item *	pprune_cond
	)

Perform partition pruning for a given table and condition.

Parameters

thd	Thread handle
table	Table to perform partition pruning for
query_block	Query block the table is part of
pprune_cond	Condition to use for partition pruning

Note

This function assumes that lock_partitions are setup when it is invoked. The function analyzes the condition, finds partitions that need to be used to retrieve the records that match the condition, and marks them as used by setting appropriate bit in part_info->read_partitions In the worst case all partitions are marked as used. If the table is not yet locked, it will also unset bits in part_info->lock_partitions that is not set in read_partitions.

This function returns promptly if called for non-partitioned table.

Returns

Operation status

Return values

true	Failure
false	Success