Re: [PATCH] Improve EXPLAIN ANALYZE overhead by sampling

On Tue, 2006-05-09 at 22:37 +0200, Martijn van Oosterhout wrote:
> This was a suggestion made back in March that would dramatically reduce
> the overhead of EXPLAIN ANALYZE on queries that loop continuously over
> the same nodes.
>
> http://archives.postgresql.org/pgsql-hackers/2006-03/msg01114.php
>
> As you can see, the overhead goes from 5.7 seconds to 0.2 seconds.
> Obviously this is an extreme case, but it will probably help in a lot
> of other cases people have been complaining about.

This seems much more useful behaviour than currently. Running an EXPLAIN
ANALYZE for large queries can be a real pain, especially on a production
box which is in live use - so tuning a test tool has a meaningful effect
on other users performance too.

There's a lot of thought gone in here, so I'd vote yes, though without
having done a detailed code review.

--
Simon Riggs
EnterpriseDB http://www.enterprisedb.com