Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1szvMb-008iSQ-08 for pgsql-bugs@arkaria.postgresql.org; Sun, 13 Oct 2024 09:58:13 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.94.2) (envelope-from ) id 1szvMZ-001Td6-7S for pgsql-bugs@arkaria.postgresql.org; Sun, 13 Oct 2024 09:58:11 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1szvMY-001Tcy-OS for pgsql-bugs@lists.postgresql.org; Sun, 13 Oct 2024 09:58:11 +0000 Received: from mail-pf1-x42e.google.com ([2607:f8b0:4864:20::42e]) by makus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1szvMS-000eeP-Gj for pgsql-bugs@lists.postgresql.org; Sun, 13 Oct 2024 09:58:09 +0000 Received: by mail-pf1-x42e.google.com with SMTP id d2e1a72fcca58-71e06ba441cso2826393b3a.1 for ; Sun, 13 Oct 2024 02:58:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1728813483; x=1729418283; darn=lists.postgresql.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=7DhYni2KqAag8T3tsmW+PkDVps6LhMJLDkBI2ZWWTBM=; b=fCZMXLYJURX63SJDks6jc2XOANfaZ3dJ/UiBUq4HjyfFZJrnqv5NdQcr2a29A9A1tb GnkFjJCyC+cQfpGVcMHSOKCw2GtXGnc8eOmR+TVo3b+ySaYo96oVq7V9s6j+HH/UWNEF esa1lbRjBkJlLJJBpl/Ml5ljlVlBflTa+XJ7NjB6mh7mRUOOkPwQbOBncvz0bXzJCdD6 MovBRoeIeWQ4Dk686P/3RVbfHGWr97hLnYbX8AwoY31ZbZ01TLFJuiKib1+H2HC/k1bX z2kQshRqNr/zmNmxF6otjp/4L6XS68Z+sjIHkzOpm+VvLdMRKhPgX/fSpBLSGDP+0FyM JY0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728813483; x=1729418283; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7DhYni2KqAag8T3tsmW+PkDVps6LhMJLDkBI2ZWWTBM=; b=vH9eRFN6RQ0TBZS96QXlBv/wHOORCXC6PTWdlunz9C4zFMIZBPIJlFgYKkAcA0qbK4 BkzoGCIwol9UGsq1cxTbfSGvrGm/Jkw3bWzvtfggKflWOXx+13lBEPEr1bOLwjIMcg+J Q97EWdyq5jn8uw6khQ7KxYMSA0dGY2/hS4eBhMUjp8UGNmNVmvAPvq5Y71BLoBDNQ2xs Hc85swk6jX8/k/CSnx4PGgN3vae4xPloFj0JoqFaxvaB7TcEsoUTd2RdGMdzTOkBVii1 rFrT5+47PB6rfJkXIRw5khB/cJudF/tL4YSgHOsEZkf/KllGMzWEFDdkC9dv2W2OVhwU GsUw== X-Forwarded-Encrypted: i=1; AJvYcCVPLl64Yrkl3PqY4+0KVOLelU0NDW8cVD9pfzrktnrWIG06aiWb8T4K8z6RiIcvylZ2Vq6CCJUeOTdL@lists.postgresql.org X-Gm-Message-State: AOJu0YyMead3kfTf+NhEfi0cUQF09B52NKuwJbDw0NXdb8CUiFIo3aCp y80KlNwZNxopMdDsVz6VOMxEfNZJgxZUmefL4RxMUtXhaqLez5oJ X-Google-Smtp-Source: AGHT+IGnyTOZ58zC5XFJf6xVQPyWIgmu4a6AHyAkbtyJd3y5A8czQEJO6SwXcajv9mVUeCo2uJZM/g== X-Received: by 2002:a05:6a00:4612:b0:71d:feda:9939 with SMTP id d2e1a72fcca58-71e37e4bfe1mr14741213b3a.4.1728813483418; Sun, 13 Oct 2024 02:58:03 -0700 (PDT) Received: from [192.168.1.175] ([103.206.205.199]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71e5ddf2960sm790268b3a.82.2024.10.13.02.58.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 13 Oct 2024 02:58:02 -0700 (PDT) Message-ID: <759cb12e-560c-4158-8bac-6e1e939c391f@gmail.com> Date: Sun, 13 Oct 2024 16:57:59 +0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Question of Parallel Hash Join on TPC-H Benchmark To: Ba Jinsheng Cc: Tomas Vondra , Zhang Mingli , "pgsql-bugs@lists.postgresql.org" References: <20f9671d-6f40-429b-a749-a2f53086e0dd@vondra.me> <3c7df680-97e6-4f20-ab27-65fb8282f95e@Spark> <978176f8-14a5-4f4d-8925-07d2e7dec4ce@gmail.com> <59f605ce-00f2-401b-be1e-5b684326ab6e@gmail.com> Content-Language: en-US From: Andrei Lepikhov In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk On 13/10/2024 15:57, Ba Jinsheng wrote: > Thanks for looking into it! > We are working a research project to automatically look for such cases. > If it matters for PostgreSQL, I will report more such cases. I made an attempt last year [1]. However, at least in production, it provided too many false-positive cases to trigger automatic re-optimisation [2] on each poorly estimated query plan. I wonder if you have any progress in that area. Living nearby Singapore (Chon Buri, Thailand) I would like to visit meetup related to this problem, if you organised it. Of course, reporting performance issues is always beneficial. [1] https://github.com/danolivo/pg_track_optimizer [2] https://postgrespro.com/docs/enterprise/16/realtime-query-replanning -- regards, Andrei Lepikhov