Re: performance with query
| От | Tom Lane |
|---|---|
| Тема | Re: performance with query |
| Дата | |
| Msg-id | 15037.1245353961@sss.pgh.pa.us обсуждение исходный текст |
| Ответ на | Re: performance with query ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>) |
| Ответы |
Re: performance with query
|
| Список | pgsql-performance |
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> With all the optimizer options on, and the from_collapse_limit and
> join_collapse_limit values both set to 100, run an EXPLAIN (no
> ANALYZE) on your big problem query. Let us know how long the EXPLAIN
> runs. If it gets any errors, copy and paste all available
> information. (General descriptions aren't likely to get us very far.)
> Since EXPLAIN without ANALYZE only *plans* the query, but doesn't run
> it, it should not take long to do this.
One issue here is that with the collapse limits cranked up to more than
geqo_threshold, he's going to be coping with GEQO's partially-random
plan selection; so whatever he reports might or might not be especially
reflective of day-to-day results. I'm tempted to ask that he also push
up geqo_threshold. It's possible that that *will* send the planning
time to the moon; but it would certainly be worth trying, to find out
what plan is produced.
regards, tom lane
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