Horton

Re: PITR, checkpoint, and local relations

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Greg Copeland <greg@copelandconsulting.net>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>, Christopher Kings-Lynne <chriskl@familyhealth.com.au>, "J. R. Nield" <jrnield@usol.com>, Richard Tucker <richt@multera.com>, PostgreSQL Hacker <pgsql-hackers@postgresql.org>
Date: 2002-08-05T13:41:04Z
Lists: pgsql-hackers 
Greg Copeland <greg@copelandconsulting.net> writes:
> On Sat, 2002-08-03 at 21:01, Tom Lane wrote:
>> * Local bufmgr semantics are twiddled to reflect this reality --- in
>> particular, data in local buffers can be held across transactions, there
>> is no end-of-transaction write (much less fsync).  A TEMP table that
>> isn't too large might never touch disk at all.

> Curious.  Is there currently such a criteria?  What exactly constitutes
> "too large"?

"too large" means "doesn't fit in the local buffer set".  At the moment
the maximum number of local buffers seems to be frozen at 64.  I was
thinking of exposing that as a configuration parameter while we're at
it.

			regards, tom lane