Received: from candle.pha.pa.us (candle.navpoint.com [162.33.245.46]) by postgresql.org (8.11.3/8.11.1) with ESMTP id f48I1sA86404 for ; Tue, 8 May 2001 14:01:54 -0400 (EDT) (envelope-from pgman@candle.pha.pa.us) Received: (from pgman@localhost) by candle.pha.pa.us (8.10.1/8.10.1) id f48I1ho19055; Tue, 8 May 2001 14:01:43 -0400 (EDT) From: Bruce Momjian Message-Id: <200105081801.f48I1ho19055@candle.pha.pa.us> Subject: Re: Default shared memory SGML mention In-Reply-To: <17050.988841325@sss.pgh.pa.us> "from Tom Lane at May 2, 2001 06:08:45 pm" To: Tom Lane Date: Tue, 8 May 2001 14:01:43 -0400 (EDT) CC: PostgreSQL-documentation X-Mailer: ELM [version 2.4ME+ PL90 (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII X-Archive-Number: 200105/41 X-Sequence-Number: 722 > Bruce Momjian writes: > > so by my computations, we need about 700k added to the shared buffer > > cache area. The documentation says to add 512k, not 700k. > > This would depend on your -N setting. > > A little experimentation shows that the present multiplier for -B is > about 8350 bytes and the multiplier for -N about 14580 bytes on my > system (HPUX), which extrapolates to a fixed base of about 250K plus > the -B and -N contributions. In reality I believe the computation > is somewhat nonlinear, but that's probably close enough for starters. I have updated the SGML sources to say for default shared memory values: 250 kB + 8192 * buffers or infinity Of course, buffers is 2 * connections by default. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026