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 1onT94-00040k-Or for pgsql-hackers@arkaria.postgresql.org; Tue, 25 Oct 2022 23:15:43 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1onT92-0000BX-Nr for pgsql-hackers@arkaria.postgresql.org; Tue, 25 Oct 2022 23:15:40 +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 1onT91-0000BO-L1 for pgsql-hackers@lists.postgresql.org; Tue, 25 Oct 2022 23:15:40 +0000 Received: from wout1-smtp.messagingengine.com ([64.147.123.24]) by magus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1onT8x-0006V2-OL for pgsql-hackers@lists.postgresql.org; Tue, 25 Oct 2022 23:15:39 +0000 Received: from compute2.internal (compute2.nyi.internal [10.202.2.46]) by mailout.west.internal (Postfix) with ESMTP id F2812320092F; Tue, 25 Oct 2022 19:15:30 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute2.internal (MEProxy); Tue, 25 Oct 2022 19:15:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:date:date:feedback-id:feedback-id:from:from :in-reply-to:in-reply-to:message-id:mime-version:reply-to:sender :subject:subject:to:to:x-me-proxy:x-me-proxy:x-me-sender :x-me-sender:x-sasl-enc; s=fm3; t=1666739730; x=1666826130; bh=Z ebsWseO0gF9MfqO2WVXUS2+YPiPWEGVStS97dLXaXE=; b=WT5iojJZVhJG+tcmT Sf3TQHqqJVzl0w5w5QJyIiATQQCkRFlFpCs68BrAW/hWkxG1/c6eaBHwefrDsMw+ z4jt7XaK3g8uRZzMceoHd5A4C2XloWYODMhY2Mb6gfnMSQP1xfkyyGgI9g53cCOo Ja+1nynXZz1ckFIULW0XsoUX6B9yqUsCHZsMG5A+ynnF8qtDgArZ/u2QfhGis+v1 5Aa8PLxt6BJBnDTMGSqPB+cD+SPhJpKktgqGQZnZ2HXEAuidh1vGbOrC4yrDdam1 GuHbtCOfe6r8I0E0L/QvnRer2qg2SIdhBOkwEY0JRx1LXq03O6gXjKUIy+FIjC/v FTpcw== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvgedrtddugddvtdcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpeffhffvvefukfggtggugfgjsehtkeertddttdejnecuhfhrohhmpeetlhhvrghr ohcujfgvrhhrvghrrgcuoegrlhhvhhgvrhhrvgesrghlvhhhrdhnohdqihhprdhorhhgqe enucggtffrrghtthgvrhhnpedvkedtffduffdtffffheffhfejjefhgfeiueeukeejkeff gfdufffhudffffeuveenucffohhmrghinhepvghnthgvrhhprhhishgvuggsrdgtohhmne cuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomheprghlvhhh vghrrhgvsegrlhhvhhdrnhhoqdhiphdrohhrgh X-ME-Proxy: Feedback-ID: ia2694551:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 25 Oct 2022 19:15:29 -0400 (EDT) Received: by perhan.alvh.no-ip.org (Postfix, from userid 1000) id A288C7D; Wed, 26 Oct 2022 01:15:32 +0200 (CEST) Date: Wed, 26 Oct 2022 01:15:32 +0200 From: Alvaro Herrera To: "Finnerty, Jim" Cc: Tom Lane , Japin Li , Justin Pryzby , "pgsql-hackers@lists.postgresql.org" Subject: Re: parse partition strategy string in gram.y Message-ID: <20221025231532.ndofmybeizfcaclj@alvherre.pgsql> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk On 2022-Oct-25, Finnerty, Jim wrote: > Or if you know the frequencies of the highly frequent values of the > partitioning key at the time the partition bounds are defined, you > could define hash ranges that contain approximately the same number of > rows in each partition. A parallel sequential scan of all partitions > would then perform better because data skew is minimized. This sounds very much like list partitioning to me. -- Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/ "The problem with the future is that it keeps turning into the present" (Hobbes)