Re: capturing/viewing sort_mem utilization on a per query basis

On Wed, 02 Feb 2005 12:58:49 -0500, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Lonni J Friedman <netllama@gmail.com> writes:
> > On Wed, 02 Feb 2005 12:13:59 -0500, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> Hmm, looks like a hash join ran out of memory.  What PG version is this
> >> again, and what do you have sort_mem set to?  Can you show an EXPLAIN
> >> for the query that is failing like this?
>
> > I've attached the explain for the query that is blowing up.
>
> One of the three Hash steps must be absorbing a whole lot more rows than
> the planner is expecting, but all of them look like fairly
> straightforward estimation situations:
>
>                ->  Hash  (cost=108.96..108.96 rows=28 width=24)
>                  ->  Index Scan using mntr_subscr_usrevt on mntr_subscription sfmain_monitoringsubscriptio0
(cost=0.00..108.96rows=28 width=24) 
>                        Index Cond: (((user_id)::text = 'user1187'::text) AND ((event_operation)::text =
'update'::text))
>
>    ->  Hash  (cost=701.44..701.44 rows=34444 width=24)
>          ->  Seq Scan on field_value tracker_artifact_group0  (cost=0.00..701.44 rows=34444 width=24)
>
>              ->  Hash  (cost=5.74..5.74 rows=1 width=80)
>                    ->  Index Scan using project_path on project tracker_artifact_extension_f1  (cost=0.00..5.74
rows=1width=80) 
>                          Index Cond: (("path")::text = 'projects.meeting_broker_v3'::text)
>                          Filter: ((("path")::text = 'projects.meeting_broker_v3'::text) OR (("path")::text ~~
'projects.meeting_broker_v3.%'::text))
>
> Perhaps one of these tables hasn't been vacuumed/analyzed and is way

I'm doing a 'vacuumdb -a -z' every 15 minutes, and a full vacuum once/day.

> bigger than the planner thinks?  Can you check into how many rows
> actually meet the identified conditions?

I'm afraid i'm not clear on what i'm supposed to be checking here.
Which conditions should I be looking at?  thanks.

--
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L. Friedman                                    netllama@gmail.com
LlamaLand                       http://netllama.linux-sxs.org