MySQL Forums
Forum List  »  Performance

Advanced Search
New Topic

Re: Each morning some SQLs are very slow
Posted by: Peter Brawley
Date: May 08, 2017 06:30PM

> SQLs with "LIKE '%<sth>%'"

No indexing can help with LIKE '%...'; needs a table scan. Later in the day, performance may seem] better because MySQL can fetch the table scan from the cache.

Try to minimise use of LIKE '%...' on big tables.

Navigate: Previous Message• Next Message
Options: Reply• Quote


Subject
Views
Written By
Posted
Each morning some SQLs are very slow
1035
lisheng1 zhang1
May 08, 2017 03:43PM
Re: Each morning some SQLs are very slow
540
Peter Brawley
May 08, 2017 06:30PM
Re: Each morning some SQLs are very slow
632
Øystein Grøvlen
May 09, 2017 12:13AM
Re: Each morning some SQLs are very slow
537
lisheng1 zhang1
May 09, 2017 02:17PM
Re: Each morning some SQLs are very slow
593
Øystein Grøvlen
May 10, 2017 08:10AM
Re: Each morning some SQLs are very slow
499
lisheng1 zhang1
May 10, 2017 02:40PM


Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.