Re: R: R: slow seqscan after vacuum analize - Mailing list pgsql-admin

From Tom Lane
Subject Re: R: R: slow seqscan after vacuum analize
Date
Msg-id 5732.1076009625@sss.pgh.pa.us
Whole thread Raw
In response to R: R: slow seqscan after vacuum analize  ("Edoardo Ceccarelli" <eddy@axa.it>)
Responses Re: R: R: slow seqscan after vacuum analize  ("Edoardo" <eddy@axa.it>)
List pgsql-admin
"Edoardo Ceccarelli" <eddy@axa.it> writes:
> Given a query that HAS to be executed with a seqscan I have noticed an
> increase in time comparing before and after the vacuum.

This is really hard to believe --- I cannot think of any mechanism that
would result in that effect.  Unless the vacuum were flushing the
kernel's disk cache, but the effects of that would only persist for one
scan.  You did say that the increased time is repeatable if you do
multiple seqscans after the vacuum?

            regards, tom lane

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