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Each morning some SQLs are very slow
Posted by: lisheng1 zhang1
Date: May 08, 2017 03:43PM

We are using mySQL 5.5 and move to 5.7 gradually. Recently we found one problem in both 5.5 and 5.7:

In each morning we found some SQLs are rather slow (take close to a minute, typically SQLs with "LIKE '%<sth>%'" or fulltext search), later if we perform same or similar SQLs again (even with SQL_NO_CACHE), the performance is OK (within 10s). What is the cause for this initial slowness (as if mySQL periodically needs to recreate some cache)?

This happened in both 5.5 and 5.7, but we are more concerned about 5.7.

Really appreciate if you could shed some lights on this issue and suggest how to avoid the initial slowness?

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Each morning some SQLs are very slow
May 08, 2017 03:43PM

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