Re: benchmarking the query planner

Alvaro Herrera wrote:
> Robert Haas escribi?:
> > > Which raises the issue, if we could get better statistics by passing
> > > the whole table, why not do that when VACUUM ANALYZE is run?
> > 
> > I think the reason is "because the next autovacuum would undo it".
> 
> Is there any way to "merge" the statistics?  i.e. if a full table scan
> is done to compute precise statistics, and later a regular analyze scan
> is done, then perhaps instead of clobbering the previous stats, you
> merge them with the new ones, thus not completely losing those previous
> ones.

Crazy idea, but if a partial analyze finds that 5% of the table has
changed since the last full analyze, but 10% of the statistics are
different, we know something is wrong.  ;-)

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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