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Re: [HACKERS] ANALYZE getting dead tuple count hopelessly wrong

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com>
Cc: "Stuart Brooks" <stuartb(at)cat(dot)co(dot)za>, pgsql-general(at)postgresql(dot)org, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [HACKERS] ANALYZE getting dead tuple count hopelessly wrong
Date: 2008-03-31 19:52:46
Message-ID: 19331.1206993166@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-hackers
"Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com> writes:
> On Mon, Mar 31, 2008 at 9:02 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> It looks like there's no trivial way to get ANALYZE to do things that
>> way, though.  heap_release_fetch() doesn't distinguish a DEAD line
>> pointer from an unused or redirected one.  But in the current
>> implementation of ANALYZE there's really no benefit to using
>> heap_release_fetch anyway --- it always examines all line pointers
>> on each selected page, so we might as well rewrite it to use a simple
>> loop more like vacuum uses.

> I agree. I would write a patch on these lines, unless you are already on to it.

Please do --- I have a lot of other stuff on my plate.

			regards, tom lane

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