From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Janek Sendrowski" <janek12@web.de>
cc: pgsql-performance@postgresql.org
Subject: Re: ORDER BY using index, tsearch2 [READ THIS!]
In-reply-to: 
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Comments: In-reply-to "Janek Sendrowski" <janek12@web.de>
 message dated "Wed, 11 Dec 2013 23:31:48 +0100"
Date: Wed, 11 Dec 2013 18:33:32 -0500
Message-ID: <16510.1386804812@sss.pgh.pa.us>
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Sender: pgsql-performance-owner@postgresql.org

"Janek Sendrowski" <janek12@web.de> writes:
> How can I use this ORDER BY using index feature presented in this implementation.
> It doesn't seem to be in use, when I have a look in my query plan.
> It still does an cost intensive Bitmap Heap Scan and a Bitmap Index scan.
> I also can't find the "><" operator in any introduction of the tsearch2 extension.
> Is it just an idea?

We're not in the habit of documenting nonexistent features, if that's what
you mean.  However, you've not provided nearly enough information for
anyone to help you; at minimum, the index definitions you have, the query
you gave, the plan you got, and the exact PG version would be critical
information.  More information about asking answerable questions can be
found here:
https://wiki.postgresql.org/wiki/Slow_Query_Questions

Also, I'm a bit troubled by your reference to tsearch2, because that
contrib module is obsolete, and has been since well before any PG version
that has a feature like what I think you're asking about.  So I wonder if
you are reading documentation not applicable to the version you're working
with.

			regards, tom lane


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