Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1coHEF-0006Cg-Hy for pgsql-hackers@arkaria.postgresql.org; Wed, 15 Mar 2017 22:17:11 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1coHEF-0008Cb-4d for pgsql-hackers@arkaria.postgresql.org; Wed, 15 Mar 2017 22:17:11 +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 4.84_2) (envelope-from ) id 1coHEE-0008CD-5R for pgsql-hackers@postgresql.org; Wed, 15 Mar 2017 22:17:10 +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 4.84_2) (envelope-from ) id 1coHEC-0001IC-0c for pgsql-hackers@postgresql.org; Wed, 15 Mar 2017 22:17:08 +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 v2FMGvIJ009138; Wed, 15 Mar 2017 18:16:57 -0400 From: Tom Lane To: Andres Freund cc: pgsql-hackers@postgresql.org, Heikki Linnakangas , Tomas Vondra Subject: Re: WIP: Faster Expression Processing v4 In-reply-to: <20170315220610.wx6pzmsbdjf5a7gs@alap3.anarazel.de> References: <20170314065259.ffef4tfhgbsaieoe@alap3.anarazel.de> <69b7bb0e-8dab-3d39-1a89-3c6ab6409f64@iki.fi> <20170314224706.nxvtapenky6eom3z@alap3.anarazel.de> <3086.1489606408@sss.pgh.pa.us> <855716B2-7522-4C79-A50E-2EB8E609764F@anarazel.de> <3401.1489606882@sss.pgh.pa.us> <20170315195838.2dqr2v674u4qwxw4@alap3.anarazel.de> <4542.1489608434@sss.pgh.pa.us> <20170315205732.bwb2wh5o5ix2vv4b@alap3.anarazel.de> <7583.1489613626@sss.pgh.pa.us> <20170315220610.wx6pzmsbdjf5a7gs@alap3.anarazel.de> Comments: In-reply-to Andres Freund message dated "Wed, 15 Mar 2017 15:06:10 -0700" MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <9136.1489616217.1@sss.pgh.pa.us> Date: Wed, 15 Mar 2017 18:16:57 -0400 Message-ID: <9137.1489616217@sss.pgh.pa.us> X-Pg-Spam-Score: -1.9 (-) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-hackers Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org Andres Freund writes: > On 2017-03-15 17:33:46 -0400, Tom Lane wrote: >> We could make the planner mark each table scan node with the highest >> column number that the plan will access, and use that to drive a >> slot_getsomeattrs call in advance of any access to tuple contents. > probably isn't sufficient - we build non-virtual tuples in a good number > of places (sorts, tuplestore using stuff like nodeMaterial, nodeHash.c > output, ...). I suspect it'd have measurable negative consequences if > we removed the deforming logic for all expressions/projections above > such nodes. I guess we could just do such a logic for every Plan node? [ scratches head... ] What deforming logic do you think I'm proposing removing? regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers