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From: twoflower <standa.kurik@gmail.com>
To: pgsql-performance@postgresql.org
Subject: Re:  Re: Query > 1000× slowdown after adding datetime comparison
Date: Mon, 31 Aug 2015 12:46:56 -0700 (MST)
Message-ID: <1441050416677-5864088.post@n5.nabble.com> (raw)
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David G Johnston wrote
> What happens if you pre-compute the date condition and hard code it?

I created a new boolean column and filled it for every row in DOCUMENT with
*(doc.date_last_updated >= date(now() - '171:00:00'::interval))*, reanalyzed
the table and modified the query to just compare this column to TRUE. I
expected this to be very fast, considering that a (to me, anyway) similar
query also containing a constant value comparison finishes immediately.
However, the query is running now for 4 minutes already. That's really
interesting.



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