Received: from maia.hub.org (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 72C896331D1 for ; Wed, 24 Jun 2009 09:14:11 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 47992-07 for ; Wed, 24 Jun 2009 09:14:10 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from titania.wxnz.net (titania.wxnz.net [58.28.4.13]) by mail.postgresql.org (Postfix) with ESMTP id 4333B632F94 for ; Wed, 24 Jun 2009 09:14:09 -0300 (ADT) Received: from gonzo (ip-118-90-143-151.xdsl.xnet.co.nz [118.90.143.151]) by titania.wxnz.net (Postfix) with ESMTP id 5C1551DB80AA for ; Thu, 25 Jun 2009 00:14:06 +1200 (NZST) Received: from news by gonzo with local (Exim 4.69) (envelope-from ) id 1MJRMV-0007tN-VW for pgsql-sql@postgresql.org; Thu, 25 Jun 2009 00:13:59 +1200 To: pgsql-sql@postgresql.org Path: not-for-mail From: Jasen Betts Newsgroups: gmane.comp.db.postgresql.sql Subject: Re: Client-side compression Date: 24 Jun 2009 12:13:59 GMT Organization: Dis (not Dat) Organisation Lines: 30 Message-ID: References: <4A413B6D.5070200@gmail.com> NNTP-Posting-Host: localhost Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: reversiblemaps.ath.cx 1245845639 29102 127.0.0.1 (24 Jun 2009 12:13:59 GMT) X-Face: ?)Aw4rXwN5u0~$nqKj`xPz>xHCwgi^q+^?Ri*+R(&uv2=E1Q0Zk(>h!~o2ID@6{uf8s; a +M[5[U[QT7xFN%^gR"=tuJw%TXXR'Fp~W; (T"1(739R%m0Yyyv*gkGoPA.$b,D.w:z+<'"=-lVT?6 {T?=R^:W5g|E2#EhjKCa+nt":4b}dU7GYB*HBxn&Td$@f%.kl^:7X8rQWd[NTc"P"u6nkisze/Q; 8 "9Z{peQF,w)7UjV$c|RO/mQW/NMgWfr5*$-Z%u46"/00mx-,\R'fLPe.)^ User-Agent: slrn/pre1.0.0-2 (Linux) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200906/98 X-Sequence-Number: 32703 On 2009-06-23, Rob Sargent wrote: > > Not sure if this belongs here or on the admin or performance list. > Apologies if so. (And this may be a second posting as the first was from > an un-registered account. Further apologies) > > My assumption is that any de/compression done by postgres would be > server-side. there may already be compression of the communication stream (probably not on unix sockets) > We're considering minimizing bandwidth utilization by using client-side > compression on a column value that will typically be multi-megabyte in > size. We would use ALTER TABLE SET STORAGE EXTERNAL to prevent the > server from un-necessary compression. > > Is this generally worthwhile? I haven't found any thread on the subject > of client-side compress so any pointer more than welcome. we recently switched from uncompressed pixmaps to JPEG data for some stored images. we have not tested performance but have certainly not noticed a decrease in performance. > Is there a great penalty for a query which delves into the value, given > that the server will not be aware it's compressed? I assume we're > pretty much on our own to prevent such actions (i.e. the app can never > query against this column via sql). It just looks like data to the server.