Horton

Re: pg_upgrade and statistics

Andrew Dunstan <andrew@dunslane.net>

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From: Andrew Dunstan <andrew@dunslane.net>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Bruce Momjian <bruce@momjian.us>, Kevin Grittner <Kevin.Grittner@wicourts.gov>, Peter Eisentraut <peter_e@gmx.net>, Daniel Farina <daniel@heroku.com>, Greg Stark <stark@mit.edu>, pgsql-hackers <pgsql-hackers@postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2012-03-13T23:28:53Z
Lists: pgsql-hackers 

On 03/13/2012 06:30 PM, Robert Haas wrote:
> On Tue, Mar 13, 2012 at 5:42 PM, Bruce Momjian<bruce@momjian.us>  wrote:
>> What is the target=10 duration?  I think 10 is as low as we can
>> acceptably recommend.  Should we recommend they run vacuumdb twice, once
>> with default_statistics_target = 4, and another with the default?
> I'm not sure why we're so glibly rejecting Dan's original proposal.
> Sure, adjusting pg_upgrade when we whack around pg_statistic is work,
> but who ever said that a workable in-place upgrade facility would be
> maintenance-free?  We're operating under a number of restrictions
> imposed by the need to be pg_upgrade-compatible, and this doesn't
> strike me as a particularly severe one by comparison -- we can always
> arrange to NOT migrate statistics between incompatible versions; that
> doesn't mean that we shouldn't migrate them when they ARE compatible.
> Also, unlike the alternatives thus far proposed, Dan's idea actually
> fixes the problem.

I agree.

cheers

andrew