From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dave Cramer <davecramer@gmail.com>
Cc: pgsql-performance <pgsql-performance@postgresql.org>
Subject: Re: why does this query not use a parallel query
Date: Fri, 02 Mar 2018 11:44:40 -0500
Message-ID: <30033.1520009080@sss.pgh.pa.us> (raw)
In-Reply-To: <CADK3HHKCxitL24RVc8YwBOdeE8c0oXzonw6jBeCi_TPwewShsg@mail.gmail.com>
References: <CADK3HHKCxitL24RVc8YwBOdeE8c0oXzonw6jBeCi_TPwewShsg@mail.gmail.com>
Dave Cramer <davecramer@gmail.com> writes:
> Have a query:
> explain analyze SELECT minion_id FROM mob_player_mob_118 WHERE player_id =
> 55351078;
> Index Only Scan using mob_player_mob_118_pkey on mob_player_mob_118
> (cost=0.44..117887.06 rows=4623076 width=4) (actual time=0.062..3716.105
> rows=4625123 loops=1)
I don't think we have parallel IOS yet (I might be wrong). If so,
it probably thinks this is cheaper than the best available parallel plan.
> If I just get the count it will use a parallel query
Likely a parallelized aggregation.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, davecramer@gmail.com
Subject: Re: why does this query not use a parallel query
In-Reply-To: <30033.1520009080@sss.pgh.pa.us>
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