Information Schema KEY_CACHES Table

The Information Schema KEY_CACHES table displays statistics about the segmented key cache, including block usage and read/write requests.

The Information Schema KEY_CACHES table shows statistics about the segmented key cache.

It contains the following columns:

Column Name	Description
KEY_CACHE_NAME	The name of the key cache
SEGMENTS	total number of segments (set to NULL for regular key caches)
SEGMENT_NUMBER	segment number (set to NULL for any regular key caches and for rows containing aggregation statistics for segmented key caches)
FULL_SIZE	memory for cache buffers/auxiliary structures
BLOCK_SIZE	size of the blocks
USED_BLOCKS	number of currently used blocks
UNUSED_BLOCKS	number of currently unused blocks
DIRTY_BLOCKS	number of currently dirty blocks
READ_REQUESTS	number of read requests
READS	number of actual reads from files into buffers
WRITE_REQUESTS	number of write requests
WRITES	number of actual writes from buffers into files

Example

SELECT * FROM information_schema.KEY_CACHES \G ********************** 1. row ********************** KEY_CACHE_NAME: default SEGMENTS: NULL SEGMENT_NUMBER: NULL  FULL_SIZE: 134217728  BLOCK_SIZE: 1024  USED_BLOCKS: 36  UNUSED_BLOCKS: 107146  DIRTY_BLOCKS: 0  READ_REQUESTS: 40305  READS: 21 WRITE_REQUESTS: 19239  WRITES: 358

_{This page is licensed: CC BY-SA / Gnu FDL}