Re: pg_upgrade and statistics

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.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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