Re: Displaying accumulated autovacuum cost

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>

To: Alvaro Herrera <alvherre@commandprompt.com>

Cc: Greg Smith <greg@2ndquadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>

Date: 2011-11-26T01:10:51Z

Lists: pgsql-hackers

Attachments

dirty_buffers.patch (application/octet-stream) patch

On Fri, Nov 25, 2011 at 11:39 AM, Alvaro Herrera
<alvherre@commandprompt.com> wrote:
> I'm going to push this now anyway, thanks.

This patch adds a count of the number of buffers dirtied to VACUUM,
but it strikes me that it would be useful to add similar tracking to
pgBufferUsage.  Attached is a patch for that.  You can see the new
counters through pg_stat_statements or with EXPLAIN (ANALYZE,
BUFFERS).  This is useful because the number of buffers that a query
*writes* doesn't necessarily have much to do with anything - it may
end up writing buffers dirtied by other queries while being read-only
itself, or conversely it may not write anything at all even though it
dirties quite a bit.

Thoughts?  Comments?  Objections?

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