Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lb4X9-0000ab-Vm for pgsql-hackers@arkaria.postgresql.org; Mon, 26 Apr 2021 16:56:31 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1lb4X8-0005Ih-O0 for pgsql-hackers@arkaria.postgresql.org; Mon, 26 Apr 2021 16:56:30 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lb4X8-0005Ia-H2 for pgsql-hackers@lists.postgresql.org; Mon, 26 Apr 2021 16:56:30 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by magus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lb4X1-0007tz-Vy for pgsql-hackers@lists.postgresql.org; Mon, 26 Apr 2021 16:56:30 +0000 Received: from sss1.sss.pgh.pa.us (localhost [127.0.0.1]) by sss.pgh.pa.us (8.15.2/8.15.2) with ESMTP id 13QGuDuW2267129; Mon, 26 Apr 2021 12:56:13 -0400 From: Tom Lane To: Stephen Frost cc: Bruce Momjian , Christoph Berg , Peter Eisentraut , Magnus Hagander , Fujii Masao , PostgreSQL Developers Subject: Re: compute_query_id and pg_stat_statements In-reply-to: <20210426163135.GU20766@tamriel.snowman.net> References: <35457b09-36f8-add3-1d07-6034fa585ca8@oss.nttdata.com> <20210424152220.GL7629@momjian.us> <20210424170908.GM7629@momjian.us> <1709439.1619286231@sss.pgh.pa.us> <20210426162104.GQ7629@momjian.us> <20210426163135.GU20766@tamriel.snowman.net> Comments: In-reply-to Stephen Frost message dated "Mon, 26 Apr 2021 12:31:35 -0400" MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <2267127.1619456173.1@sss.pgh.pa.us> Date: Mon, 26 Apr 2021 12:56:13 -0400 Message-ID: <2267128.1619456173@sss.pgh.pa.us> List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk Stephen Frost writes: > * Bruce Momjian (bruce@momjian.us) wrote: >> Techically, pg_stat_statements can turn on compute_query_id when it is >> loaded, even if it is 'off' in postgresql.conf, right? And >> pg_stat_statements would know if an alternate hash method is being used, >> right? > +1 on this approach. That'd make it impossible to turn off or adjust afterwards, wouldn't it? I'm afraid the confusion stemming from that would outweigh any simplicity. I would be in favor of logging a message at startup to the effect of "this is misconfigured" (as per upthread discussion), although whether people would see that is uncertain. In the end, it's not like this is the first time we've ever made an incompatible change in configuration needs; and it won't be the last either. I don't buy the argument that pg_stat_statements users can't cope with adding the additional setting. (Of course, we should be careful to call it out as an incompatible change in the release notes.) regards, tom lane