Re: [PERFORM] Re: Query > 1000× slowdown after adding datetime comparison

From: Stefan Keller <sfkeller(at)gmail(dot)com>
To: twoflower <standa(dot)kurik(at)gmail(dot)com>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: [PERFORM] Re: Query > 1000× slowdown after adding datetime comparison
Date: 2015-08-31 21:00:28
Message-ID: CAFcOn2_1tknJ95JceZY1ikP1OURwgwuRFSQX21SJTLFF+ZzdRA@mail.gmail.com
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So, if I'm understanding you correctly, we're talking solely about
following clause in the query you gave initially:

WHERE doc.date_last_updated >= date(now() - '171:00:00'::interval)
which initially was
WHERE documenttype = 4
and now is being replaced by a temporary (I'd say derived) column
WHERE updated
?

In any case - I have to go - but run http://explain.depesz.com/ and
give a weblink to the explain plans of your queries.

-S.

2015-08-31 22:30 GMT+02:00 twoflower <standa(dot)kurik(at)gmail(dot)com>:
> I did not. I wanted to compare this query to the one I tried before, having
> *documenttype = 4* as the sole condition. That one was very fast and the
> *documenttype* was not indexed either.
>
> But this query, using the new temporary column, still runs, after 48
> minutes...
>
>
>
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