Re: Bloat issue on 8.3; autovac ignores HOT page splits? - Mailing list pgsql-performance

From Robert Haas
Subject Re: Bloat issue on 8.3; autovac ignores HOT page splits?
Date
Msg-id AANLkTi=n6RCz_RSGhY4+AG6CbYWjLbKX6ohEvHoKNE+N@mail.gmail.com
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In response to Bloat issue on 8.3; autovac ignores HOT page splits?  (Josh Berkus <josh@agliodbs.com>)
Responses Re: Bloat issue on 8.3; autovac ignores HOT page splits?
List pgsql-performance
On Mon, Jan 24, 2011 at 9:26 PM, Josh Berkus <josh@agliodbs.com> wrote:
> It looks to me like autovacuum doesn't ever consider when HOT updates
> lead to page splits, and so require vacuuming.  Or am I diagnosing it wrong?

I'm not sure what you mean by a page split.  An update wherein the new
heap tuple won't fit on the same page as the existing heap tuple
should be treated as non-HOT.  But nothing gets split in that case.  I
think of a page split as an index event, and if these are HOT updates
there shouldn't be any index changes at all.

Can we see those stats again with n_tup_ins/upd/del?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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