MySQL Performance: MySQL => Strange behaviour on RH4.0 with MySQL 5.037

Strange behaviour on RH4.0 with MySQL 5.037 [message #1265]

Wed, 16 May 2007 04:48

olson
Messages: 1
Registered: May 2007

Junior Member

Hi All,

We have some strange results on a Redhat 4.0 server.

When executing a query, the server directly going to 'copying to tmp table' and the server is finished after 1-2 minutes.

Now,
Same software, same db, same my.cnf on a Windows OR FreeBSD server, the 'copying to tmp table' does not occur.
Query time 8-10 seconds! both FreeBSD and Windows servers are older machines with less ram Our linux machine has 4 gig.

Ok.
Analysing the query and DB.
OOPS: missing some indexes. Adding them:

Cool!! our linux machine is now finished in 8 seconds. (copying to tmp table shows up for only 2-3 seconds now)
BUT
Windows and FreeBSD now needs more time than before!!!
(18-20 seconds)

This is complete weird.
Does the mysql optimizer do some strange things under redhat?

Don't know where to start looking now.
Anyone?

linux machine: dell 2950 2x dualcore xeon 4gig mem
Freebsd: dell dualcore 1,6 2 gig mem
Windows: Amd 1800 512mb

ALL myisam
WHY does the 'copying to tmp table' not occur on the other machines.

Thanks,
Olaf

[Updated on: Wed, 16 May 2007 04:57]

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