| From: | Matteo Beccati <php(at)beccati(dot)com> |
|---|---|
| To: | Alessandro Baretta <a(dot)baretta(at)barettadeit(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: 500x speed-down: Wrong query plan? |
| Date: | 2006-01-09 15:02:18 |
| Message-ID: | 43C27AFA.7060604@beccati.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Hi Alessandro,
> Nested Loop (cost=0.00..1017.15 rows=1 width=1146) (actual
> time=258.648..258.648 rows=0 loops=1)
> -> Seq Scan on ubicazione (cost=0.00..1011.45 rows=1 width=536)
> (actual time=0.065..51.617 rows=12036 loops=1)
> Filter: ((id_ente = 'dmd'::text) AND (allarme IS NULL) AND
> (manutenzione IS NULL))
The problem seems here. The planner expects one matching row (and that's
why it chooses a nested loop), but 12036 rows are matching this condition.
Are you sure that you recentrly ANALYZED the table "ubicazione"? If so,
try to increase statistics for the id_ente column.
P.S.
There is also an italian mailing list, if you are interested :)
Best regards
--
Matteo Beccati
http://phpadsnew.com
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