From: Tom Lane <tgl@sss.pgh.pa.us>
To: Lars Aksel Opsahl <Lars.Opsahl@nibio.no>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Fast insert, but slow join and updates for table with 4 billion rows
Date: Mon, 24 Oct 2016 08:52:08 -0400
Message-ID: <21210.1477313528@sss.pgh.pa.us> (raw)
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Lars Aksel Opsahl <Lars.Opsahl@nibio.no> writes:
> In this example I have two tables one with 4 billion rows and another with 50000 rows and then I try to do a standard simple join between this two tables and this takes 397391 ms. with this SQL (the query plan is added is further down)
This particular query would work a lot better if you had an index on
nora_bc25_observation (point_uid_ref, epoch), ie both join columns
in one index. I get the impression that that ought to be the primary
key of the table, which would be an even stronger reason to have a
unique index on it.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, Lars.Opsahl@nibio.no
Subject: Re: Fast insert, but slow join and updates for table with 4 billion rows
In-Reply-To: <21210.1477313528@sss.pgh.pa.us>
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