Re: poor pefrormance with regexp searches on large tables

From: Tomas Vondra <tv(at)fuzzy(dot)cz>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: poor pefrormance with regexp searches on large tables
Date: 2011-08-10 17:15:44
Message-ID: 4E42BCC0.3010007@fuzzy.cz
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Dne 10.8.2011 19:01, Grzegorz Blinowski napsal(a):
> However, changing shared_mem didn't help. We also checked system I/O
> stats during the query - and in fact there is almost no IO (even with
> suboptimal shared_memory). So the problem is not disk transfer/access
> but rather the way Postgres handles regexp queries... As I have wirtten
> it is difficult to rewrite the query syntax (the SQL generation in this
> app is quite complex), but it should be relatively easy to at least join
> all OR clauses into one regexp, I can try this from the psql CLI. I will
> post an update if anything interesting happens...

Can you post EXPLAIN ANALYZE, prefferably using explain.depesz.com?

Tomas

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