Path: news.easynews.com!newsfeed1.easynews.com!easynews.com!easynews!nntp2.aus1.giganews.com!nntp.giganews.com!nntp3.aus1.giganews.com!nntp.metrocast.net!news.metrocast.net.POSTED!not-for-mail NNTP-Posting-Date: Mon, 03 Mar 2003 17:47:09 -0600 From: "Bill Todd" Newsgroups: comp.os.vms,comp.databases.oracle.server References: <3E63C5E9.88569D3F@eps.zko.dec.com> Subject: Re: oracle benchmarks on VMS Date: Mon, 3 Mar 2003 18:47:03 -0500 Organization: maybe X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Message-ID: Lines: 29 NNTP-Posting-Host: 207.5.223.119 X-Trace: sv3-rILHkTWAq0FZWR7vbggjkD0tIdqO5/XhtfdmewBfXPcTSWibhmItxjFj4DhBrczMrdxki/IXu0wc/kS!0WrHbXDmHzKROeN6+V0/IPl3odxCe7SsawhvoTOwNjIWQ81Xflp5RNFEeCopa/kYx6P3xnikBpjC!VDZs X-Complaints-To: abuse@metrocast.net X-DMCA-Complaints-To: abuse@metrocast.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.1 Xref: newsfeed1.easynews.com comp.os.vms:351897 comp.databases.oracle.server:178329 X-Received-Date: Mon, 03 Mar 2003 16:47:03 MST (news.easynews.com) "Hein van den Heuvel" wrote in message news:3E63C5E9.88569D3F@eps.zko.dec.com... ... > On Unix systems the OS tends to waste time and memory buffering Oracle > data pages which are better managerd by Oracle in its buffer pool (SGA). > On many Unix implementation, for ultimate Oracle perfromance once has to > deal with hard-to-manage 'Raw Devices' to avoid said buffering. Not on the most common Unixes. Veritas' VxFS file system supports direct (unbuffered) file I/O, and it's available pretty widely (it may even be the standard file system on HP-UX - they had their fingers in some part of the HP-UX data management pie, anyway). VxFS runs on Solaris, and IIRC Sun's own file system also supports direct I/O (not too surprising, given how important Oracle is to them). Linux has some form of direct I/O in 2.4, though it may be scheduled for more massaging to eliminate some kludgery. VxFS was recently ported to AIX (I don't know whether their native JFS supports direct I/O, though). (Many Unixes support asynchronous I/O too, but AFAIK none as well as VMS: they - and the POSIX asynchrony model - never seemed to understand how completion processing should work.) - bill