From: Tom Lane <tgl@sss.pgh.pa.us>
To: Julian Scarfe <julian@avbrief.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Inheritance, unique keys and performance
Date: Sun, 13 Jan 2008 13:46:43 -0500
Message-ID: <7212.1200250003@sss.pgh.pa.us> (raw)
In-Reply-To: <01b601c855c4$8ed20a60$0600a8c0@Wilbur>
References: <01a301c85552$24ab6270$0600a8c0@Wilbur>
<21684.1200170118@sss.pgh.pa.us>
<01b601c855c4$8ed20a60$0600a8c0@Wilbur>
"Julian Scarfe" <julian@avbrief.com> writes:
>> Without the EXPLAIN ANALYZE output, nobody can say whether you have
>> interpreted your performance problem correctly or not.
> Fair enough, Tom.
Okay, so the "expensive function" isn't as expensive as all that ---
it seems to be adding only a few msec to the total runtime. The
problem you've got is that you need a nestloop-with-inner-indexscan
plan type, where the inner side is an Append group (that is, an
inheritance tree) --- and 8.1 doesn't know how to create such a plan.
If you can update to 8.2 or later it should get better.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, julian@avbrief.com
Subject: Re: Inheritance, unique keys and performance
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