Received: from sss.pgh.pa.us (sss.pgh.pa.us [216.151.103.158]) by postgresql.org (8.11.3/8.11.1) with ESMTP id f42M8rA00526 for ; Wed, 2 May 2001 18:08:53 -0400 (EDT) (envelope-from tgl@sss.pgh.pa.us) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.11.3/8.11.3) with ESMTP id f42M8jR17053; Wed, 2 May 2001 18:08:46 -0400 (EDT) To: Bruce Momjian cc: PostgreSQL-documentation Subject: Re: Default shared memory SGML mention In-reply-to: <200105021617.f42GHX811076@candle.pha.pa.us> References: <200105021617.f42GHX811076@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 02 May 2001 12:17:33 -0400" Date: Wed, 02 May 2001 18:08:45 -0400 Message-ID: <17050.988841325@sss.pgh.pa.us> From: Tom Lane X-Archive-Number: 200105/14 X-Sequence-Number: 693 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. regards, tom lane