Re: EXPLAIN BUFFERS

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Itagaki Takahiro <itagaki.takahiro@oss.ntt.co.jp>, Euler Taveira de Oliveira <euler@timbira.com>, Pgsql Hackers <pgsql-hackers@postgresql.org>
Date: 2009-10-15T15:06:23Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Oct 15, 2009 at 7:29 AM, Itagaki Takahiro
> <itagaki.takahiro@oss.ntt.co.jp> wrote:
>> EXPLAIN BUFFERS only shows 'hit', 'read' and 'temp read' in text format
>> to fit in display, but xml or json format contains all of them.

> I was very careful when I submitted the machine-readable explain patch
> to make sure that the choice of which information was displayed was
> independent of the format, and I think that we should stick with that.

I thought one of the main purposes of adding the machine-readable
formats was to allow inclusion of information that we thought too
verbose for the human-readable format.  Whether this info falls into
that category remains to be seen, but I don't agree with the premise
that the information content must always be exactly the same.

FWIW, the patch's output as it stood a few days ago (one extra line per
node, conditional on a BUFFERS option) did seem perfectly reasonable to
me, and I don't see the reason to change that format now.

			regards, tom lane