Well, Try to start checking the IOPs vs Disc. Check your iowait and the cache size.
Could you send a "create table" and the query for us? Atenciosamente, *Eduardo Fontinelle* *Chief Technology Officer | G**erencianet* Phone: +55 (31) 3603-0812 2014-08-20 12:04 GMT-03:00 Jim <j...@lowcarbfriends.com>: > Without going into specific details on queries... > > Using mysql 5.1 as provided with CentOS6, I've noticed some queries > providing what I can best explain as inconsistent optimization. The > database can be quieted to just controlled queries and at times the same > query will return very quickly when at other times may take minutes. > > I don't see the same behavior with mysql5.0 under CentOS5. The same > queries on the same data returns quickly consistently. > > When the queries run slowly they show in a process list as either in a > "copy to temp table" or "sending data" state. At first I thought query > restructuring to avoid the copy to temp table was a path to a solution, but > now I don't think so since the same query changed so that it no longer > needs a temp table will sit in the "sending data" state for a long time. > > The queries do eventually come back with correct results, but it takes > minutes rather than milliseconds (sometimes slow; sometimes fast). > > Have others seen this behavior? Any explanations? > Any reading to point to for further understanding? > > Thanks. > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/mysql > >
