| From: | Guillaume Smet <guillaume_ml(at)smet(dot)org> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | josh(at)agliodbs(dot)com, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Bad plan after vacuum analyze |
| Date: | 2005-05-11 20:59:40 |
| Message-ID: | 4282723C.5080903@smet.org |
| Views: | Whole Thread | Raw Message | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Josh, Tom,
Thanks for your explanations.
> In the meantime it seems like the quickest answer for Guillaume might
> be to try to avoid keeping any NULLs in parent_application_id.
I can't do that as the majority of the applications don't have any
parent one. Moreover, we use a third party application and we cannot
modify all its internals.
Anyway, I tried to work on the statistics as you told me and here are
the results:
ccm_perf=# ALTER TABLE acs_objects ALTER COLUMN object_id SET STATISTICS 30;
ALTER TABLE
ccm_perf=# ANALYZE acs_objects;
ANALYZE
ccm_perf=# \i query_section.sql
... correct plan ...
Total runtime: 0.555 ms
So I think I will use this solution for the moment.
Thanks a lot for your help.
Regards
--
Guillaume
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