Re: Slow delete with with cascading foreign keys

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Matthias Karlsson <matthias(at)yacc(dot)se>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Slow delete with with cascading foreign keys
Date: 2008-10-20 23:02:04
Message-ID: 5878.1224543724@sss.pgh.pa.us
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Matthias Karlsson <matthias(at)yacc(dot)se> writes:
> Tom Lane skrev:
>> If it's a reasonably modern PG version, EXPLAIN ANALYZE will break out
>> the time spent in each on-delete trigger, which should be enough to
>> answer the question.

> Thanks, that gave me something to work with. I targeted the triggers that had the most "uses", but it did not seem to
> help that much. I managed to reduce execution time with maybe 10-15%, but I'll try to apply indices more aggressively to
> see if it helps.

Hm, you still didn't mention which PG version you're using --- but if
it's pre-8.3, keep in mind that you need to start a fresh session to
get the plans for FK triggers to change.

regards, tom lane

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