Thursday, July 20, 2006

SHOW INNODB STATUS: ADAPTIVE HASH INDEX


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INSERT BUFFER AND ADAPTIVE HASH INDEX
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Ibuf for space 0: size 16812, free list len 20200, seg size 37013, is not empty
Ibuf for space 0: size 16812, free list len 20200, seg size 37013,
89630355 inserts, 89285599 merged recs, 5642191 merges
Hash table size 24902177, used cells 16368903, node heap has 39339 buffer(s)
5523.49 hash searches/s, 1663.78 non-hash searches/s


1st 2 lines show segement size, and if their are any records in the innodb_buffer_pool
Next
How many inserts where done to the insert buffer,
Then
How many records where merged
Finally
How many merges it took to merge the records. (BTREE internals)

Adaptive hash index is hash index Innodb builds for some pages to speed up row lookup replacing btree search with hash search.

These are stats explaining how many hash searches / size / and non hash searches done a second. (Hash lookups are fast)

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