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 1mDtpc-00065P-BL for pgsql-bugs@arkaria.postgresql.org; Wed, 11 Aug 2021 19:24:04 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1mDtpb-0004CG-AT for pgsql-bugs@arkaria.postgresql.org; Wed, 11 Aug 2021 19:24:03 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mDrzO-0001H1-Ok for pgsql-bugs@lists.postgresql.org; Wed, 11 Aug 2021 17:26:02 +0000 Received: from mail-gateway-shared12.cyon.net ([194.126.200.65]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mDrzH-0007gi-Vj for pgsql-bugs@lists.postgresql.org; Wed, 11 Aug 2021 17:26:01 +0000 Received: from s065.cyon.net ([149.126.4.74]) by mail-gateway-shared12.cyon.net with esmtpsa (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim) (envelope-from ) id 1mDrzD-0007Dh-84 for pgsql-bugs@lists.postgresql.org; Wed, 11 Aug 2021 19:25:52 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=iggland.com ; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:To:Subject:Sender:Reply-To:Cc: Content-ID:Content-Description; bh=M0ShsiDS9XnM1fvLLYhz7XEPOuJEKINWYxRNhCKkdfg=; b=nArxHs1S2uRP6b6Up9S7ivTVQS xZV+5O1wazbFulZNDOVLVAnoONssnpOZE7WemDQgUz+1RDNS2OZMOyJ9ssvvTlN77+rMn6k7+kw1w ksOS9mvopJQemGgYJMop3GQbtfN42k1TfsavGYR53i1eS9KpfFLGz4NPHHLJiG9pCITGgssvkxFgQ QsyrZCwQ9z8JHDlPfzRMQH7hz4Ni1bfVXWNElB2KNX3S8lwpQBP7a7n0mTtOrDM/WusGBU+3R/UGo t3fTc5bY1rGpHQJCFiySpiPKofmQcbIyIwaATQJy9mOlMZhpqDK8iaLldKPYk24ZNx3/D1KmwP+Ge engHYoUw==; Received: from [10.20.10.231] (port=28376 helo=mail.cyon.ch) by s065.cyon.net with esmtpa (Exim 4.94.2) (envelope-from ) id 1mDrzC-00Byuk-3G for pgsql-bugs@lists.postgresql.org; Wed, 11 Aug 2021 19:25:50 +0200 Subject: Re: BUG #17141: SELECT LIMIT WITH TIES FOR UPDATE SKIP LOCKED returns wrong number of rows To: pgsql-bugs@lists.postgresql.org References: <17141-913d78b9675aac8e@postgresql.org> From: Emil Iggland Message-ID: <67eecc51-ef05-2990-b039-d4ddc8c63c8a@iggland.com> Date: Wed, 11 Aug 2021 19:25:48 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <17141-913d78b9675aac8e@postgresql.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - s065.cyon.net X-AntiAbuse: Original Domain - lists.postgresql.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - iggland.com X-Get-Message-Sender-Via: s065.cyon.net: authenticated_id: emil@iggland.com X-Authenticated-Sender: s065.cyon.net: emil@iggland.com List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk FWIW, the following query exhibits the behaviour that I expect, but isn't really usable in production as I do not know how many rows to expect per worker. BEGIN; SELECT * FROM queue ORDER BY task DESC LIMIT 2 OFFSET 0 FOR UPDATE SKIP LOCKED; COMMIT;