Horton

Re: EXPLAIN BUFFERS

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp>
Cc: Robert Haas <robertmhaas@gmail.com>, Euler Taveira de Oliveira <euler@timbira.com>, Greg Smith <greg@2ndquadrant.com>, Alvaro Herrera <alvherre@commandprompt.com>, Jeff Janes <jeff.janes@gmail.com>, Pgsql Hackers <pgsql-hackers@postgresql.org>
Date: 2009-12-14T14:40:46Z
Lists: pgsql-hackers 
Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp> writes:
> Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Pushing extra arguments around would create overhead of its own ...
>> overhead that would be paid even when not using EXPLAIN at all.

> I cannot understand what you mean... The additional argument should
> not be a performance overhead because the code path is run only once
> per execution.

Hmm, maybe, but still: once you have two flags you're likely to need
more.  I concur with turning doInstrument into a bitmask as per Robert's
suggestion downthread.

			regards, tom lane