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Re: merge performance problem
Posted by: Thiago Dias Fascin
Date: December 04, 2007 04:33AM

Ok. I made a mistake, consider date_added instead of callDate.
I change the varchar uniqueid to bigint, but the result was not good enough.

Loock this: http://dev.mysql.com/doc/refman/5.0/en/merge-storage-engine.html
"Key reads are slower. When you read a key, the MERGE storage engine needs to issue a read on all underlying tables to check which one most closely matches the given key. To read the next key, the MERGE storage engine needs to search the read buffers to find the next key. Only when one key buffer is used up does the storage engine need to read the next key block. This makes MERGE keys much slower on eq_ref searches, but not much slower on ref searches. See Section 6.2.1, “Optimizing Queries with EXPLAIN”, for more information about eq_ref and ref."

How can I be sure if mysql is creating buffer for this search, I'm asking this because probably I need to have a bugger buffer. This make sense?

Or have in mysql some configuration that will improve performance for this kind of select?



Edited 1 time(s). Last edit at 12/04/2007 04:51AM by Thiago Dias Fascin.

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