Re: BUG #4899: Open parenthesis breaks query plan

From: "Peter Headland" <pheadland(at)actuate(dot)com>
To: "Greg Stark" <gsstark(at)mit(dot)edu>
Cc: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, <pgsql-bugs(at)postgresql(dot)org>
Subject: Re: BUG #4899: Open parenthesis breaks query plan
Date: 2009-07-06 17:35:19
Message-ID: 71F491F5DA99604A80DE49424BF3D02B0C088DA7@exchange8.actuate.com
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As I said further down my previous e-mail, it looks as if the optimizer
is just fine, and the problem is simply a bug in the way pgAdmin III
parses and displays EXPLAIN ANALYZE output in its graphical view.

--
Peter Headland
Architect - e.Reports
Actuate Corporation

-----Original Message-----
From: gsstark(at)gmail(dot)com [mailto:gsstark(at)gmail(dot)com] On Behalf Of Greg
Stark
Sent: Monday, July 06, 2009 10:35
To: Peter Headland
Cc: Tom Lane; pgsql-bugs(at)postgresql(dot)org
Subject: Re: BUG #4899: Open parenthesis breaks query plan

On Mon, Jul 6, 2009 at 5:40 PM, Peter Headland<pheadland(at)actuate(dot)com>
wrote:
> presence
> of a '(' character anywhere at all in the string literal triggers the
> problem. For example 'abc(def'.

Except according to that explain analyze 'abc(def' ran exactly the
speed as 'abc()def'.

This all seems much more likely to depend on the c1/an_integer_column
value you're querying for than on the string. Keep trying different
values for both columns until you find one that triggers the problem
and send the explain analyze result for that. It could be that '(' was
such a value yesterday but not today if autovacuum has run analyze
since.

--
greg
http://mit.edu/~gsstark/resume.pdf

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