Re: best way to query - Mailing list pgsql-general

From Tom Lane
Subject Re: best way to query
Date
Msg-id 749.1201276081@sss.pgh.pa.us
Whole thread Raw
In response to best way to query  (Steve Clark <sclark@netwolves.com>)
Responses Re: best way to query  (Steve Clark <sclark@netwolves.com>)
List pgsql-general
Steve Clark <sclark@netwolves.com> writes:
> explain shows:

>   Aggregate  (cost=4712921585.30..4712921585.31 rows=1 width=0)
>     ->  Seq Scan on t_event_ack_log a  (cost=103170.29..4712920878.60
> rows=282677 width=0)
>           Filter: (NOT (subplan))
>           SubPlan
>             ->  Materialize  (cost=103170.29..117301.92 rows=1016163
> width=4)
>                   ->  Index Scan using pk_tuel_eln on t_unit_event_log
>   (cost=0.00..98184.12 rows=1016163 width=4)

Yeah, that's going to suck.  A brute force solution is to see if you
can get it to switch to a "hashed subplan" by increasing work_mem.

Also, whatever is the ORDER BY for?

            regards, tom lane

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