Received: from malur.postgresql.org ([2a02:16a8:dc51::56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1g5IL4-00009p-4B for pgsql-hackers@arkaria.postgresql.org; Wed, 26 Sep 2018 22:31:22 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1g5IL1-0005Hb-R3 for pgsql-hackers@arkaria.postgresql.org; Wed, 26 Sep 2018 22:31:19 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1g5IL1-0005HU-G4 for pgsql-hackers@lists.postgresql.org; Wed, 26 Sep 2018 22:31:19 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1g5IKu-0004wO-Il for pgsql-hackers@lists.postgresql.org; Wed, 26 Sep 2018 22:31:18 +0000 Received: from sss1.sss.pgh.pa.us (localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.4/8.14.4) with ESMTP id w8QMV7Y8005743; Wed, 26 Sep 2018 18:31:07 -0400 From: Tom Lane To: Andres Freund cc: Michael Paquier , Thomas Munro , Alvaro Herrera , PostgreSQL Hackers Subject: Re: Allowing printf("%m") only where it actually works In-reply-to: <20180926214952.ol6b6kawc6u3tvu5@alap3.anarazel.de> References: <14925.1534040609@sss.pgh.pa.us> <1437.1534100930@sss.pgh.pa.us> <13183.1534624490@sss.pgh.pa.us> <30022.1534705920@sss.pgh.pa.us> <20180912070739.GK25160@paquier.xyz> <1304.1536774001@sss.pgh.pa.us> <20180914020256.GD29332@paquier.xyz> <13585.1537809527@sss.pgh.pa.us> <20180926174645.nsyj77lx2mvtz4kx@alap3.anarazel.de> <25501.1537998096@sss.pgh.pa.us> <20180926214952.ol6b6kawc6u3tvu5@alap3.anarazel.de> Comments: In-reply-to Andres Freund message dated "Wed, 26 Sep 2018 14:49:53 -0700" MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <5741.1538001067.1@sss.pgh.pa.us> Date: Wed, 26 Sep 2018 18:31:07 -0400 Message-ID: <5742.1538001067@sss.pgh.pa.us> List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk Andres Freund writes: > On 2018-09-26 17:41:36 -0400, Tom Lane wrote: >> Well, if you're unhappy about snprintf.c's performance, you could review >> https://commitfest.postgresql.org/19/1763/ >> so I can push that. In my tests, that got us down to circa 10% penalty >> for float conversions. > Uh, I can do that, but the fact remains that your commit slowed down > COPY and other conversion intensive workloads by a *significant* amount. [ shrug... ] There are other cases that got faster (particularly after the above-mentioned patch). I do not wish to consider floating-point conversion speed as the sole figure of merit for this change. If we are to consider only the worst-case, we should be reverting JIT. regards, tom lane