Re: won't drop the view
От
Oleg Lebedev
Тема
Re: won't drop the view
Дата
Msg-id
3C293ACB.4BEBA02F@waterford.org
Список
Дерево обсуждения
Re: won't drop the view Oleg Lebedev <olebedev@waterford.org>
Re: won't drop the view Tom Lane <tgl@sss.pgh.pa.us>
Thanks everybody for your help.
Deleting from pg_statistic restored view performance to the way it was
before I ran vacuum analyze.
Below I attach two files that contain explain statistics for the view before
(progress_report.txt) and after (progress_report_analyzed.txt) I ran vacuum
analyze. The first one takes about 15 secs. to complete, the second one
takes 12-13 minutes to complete.
I hope this will help you improve your query optimizer.
thanks,
Oleg
Tom Lane wrote:
> "Josh Berkus" writes:
> > Damn. I can only really help with the obvious things, and you've
> > covered most of those. That view should take a long time, given the
> > complexity ... but a long time is 30-60 seconds, not 10 minutes.
>
> I'm guessing it's ye olde stupid-choice-of-plan kind of problem.
> Unless I missed it, we have not been shown the plan currently being
> used (no, the first four lines don't do it for me...)
>
> You could probably get back to the previous, not-so-slow plan choice
> by doing "DELETE FROM pg_statistic" to remove the data collected by
> VACUUM ANALYZE. A comparison of the EXPLAIN output in that state
> vs. the EXPLAIN output in the analyzed state might be enlightening.
>
> regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: Have you checked our extensive FAQ?
>
> http://www.postgresql.org/users-lounge/docs/faq.html
execution time ~ 15sec.
NOTICE: QUERY PLAN:
Subquery Scan progress_report (cost=14648.65..14648.65 rows=4 width=128)
-> Sort (cost=14648.65..14648.65 rows=4 width=128)
-> Merge Join (cost=14644.00..14648.62 rows=4 width=128)
-> Sort (cost=11.02..11.02 rows=2 width=48)
-> Seq Scan on activity (cost=0.00..11.00 rows=2 width=48)
-> Sort (cost=14632.99..14632.99 rows=367 width=112)
-> Subquery Scan media_acts (cost=14553.17..14617.36 rows=367 width=112)
-> Aggregate (cost=14553.17..14617.36 rows=367 width=112)
-> Group (cost=14553.17..14562.34 rows=3668 width=112)
-> Sort (cost=14553.17..14553.17 rows=3668 width=112)
-> Subquery Scan stats (cost=13969.18..14336.00 rows=3668 width=112)
-> Unique (cost=13969.18..14336.00 rows=3668 width=112)
-> Sort (cost=13969.18..13969.18 rows=36682 width=112)
-> Append (cost=1.31..9744.33 rows=36682 width=112)
-> Subquery Scan *SELECT* 1 (cost=1.31..1154.05 rows=11459 width=56)
-> Hash Join (cost=1.31..1154.05 rows=11459 width=56)
-> Seq Scan on media (cost=0.00..407.59 rows=11459 width=36)
-> Hash (cost=1.25..1.25 rows=25 width=20)
-> Seq Scan on mediatypemap (cost=0.00..1.25 rows=25 width=20)
-> Subquery Scan *SELECT* 2 (cost=1313.31..4930.60 rows=20704 width=80)
-> Hash Join (cost=1313.31..4930.60 rows=20704 width=80)
-> Hash Join (cost=1283.70..3513.64 rows=21196 width=64)
-> Seq Scan on intsetmedia (cost=0.00..399.96 rows=21196 width=16)
-> Hash (cost=1154.05..1154.05 rows=11459 width=48)
-> Hash Join (cost=1.31..1154.05 rows=11459 width=48)
-> Seq Scan on media (cost=0.00..407.59 rows=11459 width=28)
-> Hash (cost=1.25..1.25 rows=25 width=20)
-> Seq Scan on mediatypemap (cost=0.00..1.25 rows=25 width=20)
-> Hash (cost=27.69..27.69 rows=769 width=16)
-> Seq Scan on set (cost=0.00..27.69 rows=769 width=16)
-> Subquery Scan *SELECT* 3 (cost=1469.06..3659.68 rows=4519 width=112)
-> Hash Join (cost=1469.06..3659.68 rows=4519 width=112)
-> Hash Join (cost=1467.74..3364.32 rows=4519 width=92)
-> Hash Join (cost=689.81..1978.41 rows=4519 width=64)
-> Hash Join (cost=585.40..1498.78 rows=9148 width=32)
-> Seq Scan on dtrowmedia (cost=0.00..164.48 rows=9148 width=16)
-> Hash (cost=306.99..306.99 rows=16799 width=16)
-> Seq Scan on dtrow (cost=0.00..306.99 rows=16799 width=16)
-> Hash (cost=102.55..102.55 rows=744 width=32)
-> Hash Join (cost=6.62..102.55 rows=744 width=32)
-> Seq Scan on dtcol (cost=0.00..32.06 rows=1506 width=16)
-> Hash (cost=5.90..5.90 rows=290 width=16)
-> Seq Scan on datatable (cost=0.00..5.90 rows=290 width=16)
-> Hash (cost=407.59..407.59 rows=11459 width=28)
-> Seq Scan on media (cost=0.00..407.59 rows=11459 width=28)
-> Hash (cost=1.25..1.25 rows=25 width=20)
-> Seq Scan on mediatypemap (cost=0.00..1.25 rows=25 width=20)
EXPLAIN
execution time ~ 12-13 mins.
NOTICE: QUERY PLAN:
Subquery Scan progress_report (cost=14687.00..14687.00 rows=2 width=128)
-> Sort (cost=14687.00..14687.00 rows=2 width=128)
-> Nested Loop (cost=14605.17..14686.99 rows=2 width=128)
-> Seq Scan on activity (cost=0.00..11.00 rows=1 width=48)
-> Subquery Scan media_acts (cost=14605.17..14671.27 rows=378 width=112)
-> Aggregate (cost=14605.17..14671.27 rows=378 width=112)
-> Group (cost=14605.17..14614.61 rows=3777 width=112)
-> Sort (cost=14605.17..14605.17 rows=3777 width=112)
-> Subquery Scan stats (cost=14003.05..14380.75 rows=3777 width=112)
-> Unique (cost=14003.05..14380.75 rows=3777 width=112)
-> Sort (cost=14003.05..14003.05 rows=37771 width=112)
-> Append (cost=1.31..9627.85 rows=37771 width=112)
-> Subquery Scan *SELECT* 1 (cost=1.31..1154.05 rows=11459 width=56)
-> Hash Join (cost=1.31..1154.05 rows=11459 width=56)
-> Seq Scan on media (cost=0.00..407.59 rows=11459 width=36)
-> Hash (cost=1.25..1.25 rows=25 width=20)
-> Seq Scan on mediatypemap (cost=0.00..1.25 rows=25 width=20)
-> Subquery Scan *SELECT* 2 (cost=1313.31..4930.60 rows=21196 width=80)
-> Hash Join (cost=1313.31..4930.60 rows=21196 width=80)
-> Hash Join (cost=1283.70..3513.64 rows=21196 width=64)
-> Seq Scan on intsetmedia (cost=0.00..399.96 rows=21196 width=16)
-> Hash (cost=1154.05..1154.05 rows=11459 width=48)
-> Hash Join (cost=1.31..1154.05 rows=11459 width=48)
-> Seq Scan on media (cost=0.00..407.59 rows=11459 width=28)
-> Hash (cost=1.25..1.25 rows=25 width=20)
-> Seq Scan on mediatypemap (cost=0.00..1.25 rows=25 width=20)
-> Hash (cost=27.69..27.69 rows=769 width=16)
-> Seq Scan on set (cost=0.00..27.69 rows=769 width=16)
-> Subquery Scan *SELECT* 3 (cost=1993.99..3543.20 rows=5116 width=112)
-> Hash Join (cost=1993.99..3543.20 rows=5116 width=112)
-> Hash Join (cost=1992.68..3209.05 rows=5116 width=92)
-> Seq Scan on media (cost=0.00..407.59 rows=11459 width=28)
-> Hash (cost=1979.89..1979.89 rows=5116 width=64)
-> Hash Join (cost=690.05..1979.89 rows=5116 width=64)
-> Hash Join (cost=585.40..1498.78 rows=9148 width=32)
-> Seq Scan on dtrowmedia (cost=0.00..164.48 rows=9148 width=16)
-> Hash (cost=306.99..306.99 rows=16799 width=16)
-> Seq Scan on dtrow (cost=0.00..306.99 rows=16799 width=16)
-> Hash (cost=102.55..102.55 rows=842 width=32)
-> Hash Join (cost=6.62..102.55 rows=842 width=32)
-> Seq Scan on dtcol (cost=0.00..32.06 rows=1506 width=16)
-> Hash (cost=5.90..5.90 rows=290 width=16)
-> Seq Scan on datatable (cost=0.00..5.90 rows=290 width=16)
-> Hash (cost=1.25..1.25 rows=25 width=20)
-> Seq Scan on mediatypemap (cost=0.00..1.25 rows=25 width=20)
EXPLAIN
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