Re: plan time of MASSIVE partitioning ...

From: Boszormenyi Zoltan <zb(at)cybertec(dot)at>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alvaro Herrera <alvherre(at)commandprompt(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>, Hans-Jürgen Schönig <postgres(at)cybertec(dot)at>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: plan time of MASSIVE partitioning ...
Date: 2010-09-10 09:14:41
Message-ID: 4C89F701.7030408@cybertec.at
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Tom Lane írta:
> Boszormenyi Zoltan <zb(at)cybertec(dot)at> writes:
>
>> equal() is called over 8 million times with or without our patch:
>>
>
> From where, though? You've provided not a shred of evidence that
> searching large ec_member lists is the problem.
>

Indeed. I have put elog(NOTICE) calls in there to see which
lists is how long. It turned out that the length of ec_members is either 0
or 1, mostly 1, but the length of eq_classes is constantly growing.
This is what I need to attack then.

> Also, did the test case you're using ever make it to the list?
>

No, because it was too large and because of the test case
accidentally contained confidential information, we asked
Bruce to delete it from the moderator queue.

Attached is a shortened test case that does the same and
also shows the same problem. The create_table.sql
creates the parent table, the table_generator.sql produces
the list of constraint excluded child tables and their indexes.

The gprof output of this is only slightly modified, the
number of equal() calls is still over 8 million, it is also
attached.

Best regards,
Zoltán Böszörményi

--
----------------------------------
Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt, Austria
Web: http://www.postgresql-support.de
http://www.postgresql.at/

Attachment Content-Type Size
create_table.sql text/plain 211 bytes
table_generator.sql text/plain 2.5 KB
gmon.log1.gz application/x-tar 125.2 KB

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