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

From Simon Riggs
Subject Re: 8.4 open item: copy performance regression?
Date
Msg-id 1245684316.31430.126.camel@ebony.2ndQuadrant
Whole thread Raw
In response to Re: 8.4 open item: copy performance regression?  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: 8.4 open item: copy performance regression?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Mon, 2009-06-22 at 11:14 -0400, Tom Lane wrote:
> Stephen Frost <sfrost@snowman.net> writes:
> > * Tom Lane (tgl@sss.pgh.pa.us) wrote:
> >> The more useful case for data load is "create or truncate it in the
> >> same transaction", of course.
> 
> > Unfortunately, WAL bypass also requires not being in archive mode with
> > no way to turn that off w/o a server restart, aiui.
> 
> Well, if you're trying to archive then you certainly wouldn't want WAL
> off, so I'm failing to see where this thread is going ...

I was thinking it might be beneficial to be able to defer writing WAL
until COPY is complete, so heap_sync would either fsync the whole heap
file or copy the whole file to WAL.

That would avoid writing WAL piecemeal because we could just backup the
whole block, plus we wouldn't write anything at all if the COPY failed.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support



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