Re: New EXPLAIN ANALYZE statement

From: Philip Warner <pjw(at)rhyme(dot)com(dot)au>
To: Martijn van Oosterhout <kleptog(at)svana(dot)org>, pgsql-patches(at)postgresql(dot)org
Subject: Re: New EXPLAIN ANALYZE statement
Date: 2001-07-21 02:04:47
Message-ID: 3.0.5.32.20010721120447.021d15b0@mail.rhyme.com.au
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At 00:49 21/07/01 +1000, Martijn van Oosterhout wrote:
>- What it does:
>Adds a new EXPLAIN ANALYZE statement which displays the plan tree, just like
>EXPLAIN, but also executes the query and collects statistics on what
>actually happened. The current statistics collected are:
>
>Time till first tuple is returned
>Time till all tuples are returned
>Total number of tuples returned
>Number of times Rescan is called
>

This is a great idea; it's a good first step in getting some stats on how
accurate the optimizer settings are, as well as how good the assumptions
are. But you probably need to collect information about IOs & buffer hits
as well. Perhaps you should look at Jan's stats collection patches and see
if you can piggyback on them somehow?

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