Re: FUNC_MAX_ARGS benchmarks

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

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

To: Joe Conway <mail@joeconway.com>

Cc: Bruce Momjian <pgman@candle.pha.pa.us>, Thomas Lockhart <lockhart@fourpalms.org>, Neil Conway <nconway@klamath.dyndns.org>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>

Date: 2002-08-05T21:31:03Z

Lists: pgsql-hackers

Well, in fact it's not just a question of disk space.

The following numbers are stats for total elapsed time of "make
installcheck" over ten trials:

NAMEDATALEN = 32, FUNC_MAX_ARGS = 16

  min  |  max  |  avg   |      stddev
-------+-------+--------+-------------------
 25.59 | 27.61 | 26.612 | 0.637003401351409

NAMEDATALEN = 64, FUNC_MAX_ARGS = 32

  min  |  max  |  avg   |     stddev
-------+-------+--------+-----------------
 26.32 | 29.27 | 27.415 | 1.0337982824947

NAMEDATALEN = 128, FUNC_MAX_ARGS = 32

  min  |  max  |  avg   |      stddev
-------+-------+--------+------------------
 27.44 | 30.79 | 29.603 | 1.26148105195622

I'm not sure about the trend of increasing standard deviation --- that
may reflect more disk I/O being done, and perhaps more checkpoints
occurring during the test.  But in any case it's clear that there's a
nontrivial runtime cost here.  Does a 10% slowdown bother you?

			regards, tom lane