Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id A95061337C04 for ; Mon, 18 Apr 2011 13:48:51 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 53971-01-8 for ; Mon, 18 Apr 2011 16:48:44 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from spinlock.commandprompt.com (host-215.commandprompt.net [207.173.203.215]) by mail.postgresql.org (Postfix) with ESMTP id C38A21337C84 for ; Mon, 18 Apr 2011 13:46:18 -0300 (ADT) Received: from localhost (localhost [127.0.0.1]) by spinlock.commandprompt.com (Postfix) with ESMTP id 3A744348046; Mon, 18 Apr 2011 09:46:12 -0700 (PDT) X-Virus-Scanned: Debian amavisd-new at commandprompt.com Received: from spinlock.commandprompt.com ([127.0.0.1]) by localhost (spinlock.commandprompt.com.commandprompt.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 1BGgy4M0RtS2; Mon, 18 Apr 2011 09:46:09 -0700 (PDT) Received: from perhan.alvh.no-ip.org (unknown [190.95.21.184]) by spinlock.commandprompt.com (Postfix) with ESMTPSA id 3208A348024; Mon, 18 Apr 2011 09:46:09 -0700 (PDT) Received: by perhan.alvh.no-ip.org (Postfix, from userid 1000) id E1F756E471; Mon, 18 Apr 2011 13:46:06 -0300 (CLST) Content-Type: text/plain; charset=UTF-8 Cc: pgsql-docs Subject: Re: Default compression level for custom format in pg_dump ? From: Alvaro Herrera To: Grzegorz Szpetkowski In-reply-to: References: Date: Mon, 18 Apr 2011 13:46:06 -0300 Message-Id: <1303145065-sup-9479@alvh.no-ip.org> User-Agent: Sup/git Content-Transfer-Encoding: 8bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.9 tagged_above=-5 required=5 tests=BAYES_00=-1.9 X-Spam-Level: X-Archive-Number: 201104/81 X-Sequence-Number: 6652 Excerpts from Grzegorz Szpetkowski's message of dom abr 17 21:26:02 -0300 2011: > Then "it goes to" zlib library. According to http://www.zlib.net/manual.html: > > "The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and > 9: 1 gives best speed, 9 gives best compression, 0 gives no > compression at all (the input data is simply copied a block at a > time). Z_DEFAULT_COMPRESSION requests a default compromise between > speed and compression (currently equivalent to level 6)." > > #define Z_DEFAULT_COMPRESSION (-1) (zlib.h) > > What do you think about adding some clarification in PostgreSQL doc ? Can this behavior be tuned externally? Say by an environment var or something. If it can, then maybe it's worth documenting it a bit more fully (including the tuning option). Otherwise I think the current docs are enough. -- Álvaro Herrera The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support