From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jim C. Nasby <jnasby@pervasive.com>
Cc: Simon Riggs <simon@2ndquadrant.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: WAL logging of SELECT ... INTO command
Date: Wed, 22 Mar 2006 10:35:26 -0500
Message-ID: <16692.1143041726@sss.pgh.pa.us> (raw)
In-Reply-To: <20060322151434.GG15742@pervasive.com>
References: <20060321122211.GU15742@pervasive.com>
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<20060322124732.GA15742@pervasive.com>
<1143032914.24487.632.camel@localhost.localdomain>
<20060322131910.GC15742@pervasive.com>
<16480.1143039965@sss.pgh.pa.us>
<20060322151434.GG15742@pervasive.com>
"Jim C. Nasby" <jnasby@pervasive.com> writes:
> Oh, so in other words, SELECT * INTO temp FROM table is inherently
> non-deterministic at the physical level, so the only way to be able to
> allow PITR to work is to duplicate all the physical changes. Darn.
Well, lemme put it this way: I'm not prepared to require that PG be
deterministic at the physical level. One obvious source of
non-determinancy is the FSM, which is likely to hand out different free
space to different transactions depending on what else is going on at
the same time. There are others, such as deliberately random
tie-breaking during btree index insertion.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, jnasby@pervasive.com, simon@2ndquadrant.com
Subject: Re: WAL logging of SELECT ... INTO command
In-Reply-To: <16692.1143041726@sss.pgh.pa.us>
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