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 1joEc7-0005Wd-87 for pgsql-hackers@arkaria.postgresql.org; Wed, 24 Jun 2020 23:15:31 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1joEc5-0000AQ-7H for pgsql-hackers@arkaria.postgresql.org; Wed, 24 Jun 2020 23:15:29 +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 1joEc5-0000AH-0A for pgsql-hackers@lists.postgresql.org; Wed, 24 Jun 2020 23:15:29 +0000 Received: from momjian.us ([72.94.173.45]) by magus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1joEby-0003dg-5P for pgsql-hackers@postgresql.org; Wed, 24 Jun 2020 23:15:28 +0000 Received: from bruce by momjian.us with local (Exim 4.92) (envelope-from ) id 1joEbt-0003yd-50; Wed, 24 Jun 2020 19:15:17 -0400 Date: Wed, 24 Jun 2020 19:15:17 -0400 From: Bruce Momjian To: Tomas Vondra Cc: Andres Freund , Robert Haas , David Rowley , Jeff Davis , Justin Pryzby , Melanie Plageman , "pgsql-hackers@postgresql.org" Subject: Re: Default setting for enable_hashagg_disk Message-ID: <20200624231517.GA13627@momjian.us> References: <8bff2e4e8020c3caa16b61a46918d21b573eaf78.camel@j-davis.com> <129c8f1739957589584d9525e1d8782eae3f412f.camel@j-davis.com> <20200624191433.5gnqgrxfmucexldm@alap3.anarazel.de> <20200624193624.fsr7lvqzgml2qvei@alap3.anarazel.de> <20200624210210.no7l4vihsw4yfvoz@development> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200624210210.no7l4vihsw4yfvoz@development> User-Agent: Mutt/1.10.1 (2018-07-13) List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk On Wed, Jun 24, 2020 at 11:02:10PM +0200, Tomas Vondra wrote: > > Indeed. And then perhaps we could eventually add some reporting / > > monitoring infrastructure for the cases where plan time and execution > > time memory estimate/usage widely differs. > > > > I wouldn't mind something like that in general - not just for hashagg, > but for various other nodes. Well, other than worrying about problems with pre-13 queries, how is this different from any other spill to disk when we exceed work_mem, like sorts for merge join. -- Bruce Momjian https://momjian.us EnterpriseDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee