Re: Interesting glitch in autovacuum - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Interesting glitch in autovacuum
Date
Msg-id 1221076463.3913.748.camel@ebony.2ndQuadrant
Whole thread Raw
In response to Interesting glitch in autovacuum  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Interesting glitch in autovacuum  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Wed, 2008-09-10 at 11:52 -0400, Tom Lane wrote:

> I'm thinking that maybe an appropriate fix is to insert a
> GetTransactionSnapshot call at the beginning of InitPostgres'
> transaction, thus ensuring that every backend has some vaguely sane
> value for RecentGlobalXmin before it tries to do any database access.

Can't we just set RecentGlobalXmin without getting a Snapshot? There's
no need for a snapshot at that point is there? Just lock ProcArrayLock,
read GlobalXmin, drop lock.

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



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