Re: 8.4 open item: copy performance regression? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: 8.4 open item: copy performance regression?
Date
Msg-id 28355.1246048234@sss.pgh.pa.us
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In response to Re: 8.4 open item: copy performance regression?  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
Responses Re: 8.4 open item: copy performance regression?  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
List pgsql-hackers
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> Regarding the fact that even with the xlog files pre-populated, the
> smaller set of xlog files is faster: I'm only guessing, but I suspect
> the battery backed RAID controller is what's defeating conventional
> wisdom here.  By writing to the same, relatively small, set of xlog
> files repeatedly, some of the actual disk writes probably evaporate in
> the BBU cache.

Yeah, sounds plausible.  How big is your BBU cache?
        regards, tom lane


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