Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id E09C9633363 for ; Wed, 4 Nov 2009 06:35:57 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 30783-07 for ; Wed, 4 Nov 2009 10:35:42 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from lo.gmane.org (lo.gmane.org [80.91.229.12]) by mail.postgresql.org (Postfix) with ESMTP id 487E763222F for ; Wed, 4 Nov 2009 06:35:46 -0400 (AST) Received: from list by lo.gmane.org with local (Exim 4.50) id 1N5dDK-0005v8-GJ for pgsql-performance@postgresql.org; Wed, 04 Nov 2009 11:35:42 +0100 Received: from lara.cc.fer.hr ([161.53.72.113]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 04 Nov 2009 11:35:42 +0100 Received: from ivoras by lara.cc.fer.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 04 Nov 2009 11:35:42 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: pgsql-performance@postgresql.org From: Ivan Voras Subject: Re: Free memory usage Sol10, 8.2.9 Date: Wed, 04 Nov 2009 11:35:23 +0100 Lines: 31 Message-ID: References: <4AF095D0.9000705@wizmail.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: lara.cc.fer.hr User-Agent: Thunderbird 2.0.0.23 (X11/20090928) In-Reply-To: <4AF095D0.9000705@wizmail.org> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.599 tagged_above=-10 required=5 tests=BAYES_00=-2.599 X-Spam-Level: X-Archive-Number: 200911/41 X-Sequence-Number: 36209 Jeremy Harris wrote: > On 11/03/2009 07:16 PM, Subbiah Stalin-XCGF84 wrote: >> All, >> >> I'm trying to understand the free memory usage and why it falls below >> 17G sometimes and what could be causing it. Any pointers would be >> appreciated. >> >> root@prod1 # prtconf >> System Configuration: Sun Microsystems sun4u >> Memory size: 32768 Megabytes >> >> [postgres@prod1 ~]$ vmstat 5 10 >> kthr memory page disk faults >> cpu >> r b w swap free re mf pi po fr de sr 1m 1m 1m m1 in sy cs us >> sy id >> 0 0 0 51713480 21130304 58 185 325 104 104 0 0 23 3 7 1 488 604 573 1 >> 2 97 >> 0 0 0 51048768 18523456 6 10 0 192 192 0 0 4 0 3 0 527 753 807 2 >> 1 97 > > Memory used by the OS for caching files is no longer free. > Free memory is wasted memory. To finish the thought: memory used by OS for caching files will be automatically given to applications that need more memory so it is "kind of" free memory. In your case, you really do have 17-18G unused memory which is practically wasted.