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 1mmcTm-0000sb-EO for pgsql-performance@arkaria.postgresql.org; Mon, 15 Nov 2021 13:57:02 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1mmcTk-0004ET-BK for pgsql-performance@arkaria.postgresql.org; Mon, 15 Nov 2021 13:57:00 +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 1mmcTj-0004EJ-U1 for pgsql-performance@lists.postgresql.org; Mon, 15 Nov 2021 13:56:59 +0000 Received: from mail-qk1-x72a.google.com ([2607:f8b0:4864:20::72a]) by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1mmcTh-0002jR-F4 for pgsql-performance@lists.postgresql.org; Mon, 15 Nov 2021 13:56:58 +0000 Received: by mail-qk1-x72a.google.com with SMTP id 193so16660277qkh.10 for ; Mon, 15 Nov 2021 05:56:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to; bh=EdxRm5/hxUrGDZ9WXdjQMKCKMljYOsXrThP8G5NlDgU=; b=b7aNY1c3YNpqQ5dJoo8kzyX3j8g3WiICnLo0trcj9I+OXfXL3bSOSv0qf4PRiFlcfp 43E0YWzKSac0UfAk4KO1pYJLRntaJPexc6zE7tftvABU9fjw+m3KmGH2Tq8v7FFr2WQN ppMm4gsojl6s0LbCStyafuljVSmzq5kl83LbMc0vO3W8+2PUtMdLxkaEdzQUmbp0B2dH l5E1Bn+yjOKeip9EqfGEcOT2xANSsxySUcXbklFaejxsLMb1EHU/ckSwS4Rqvz4sRsZG bAbmoPc8WeqZFSiMB9R7kQuDv49FiDnA+R+iNfz0CUsNSPojupI8MAVtsuTNobJgO+zy R/nQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to; bh=EdxRm5/hxUrGDZ9WXdjQMKCKMljYOsXrThP8G5NlDgU=; b=MqyU2KotFxIvxDs2CAt5yYXVldMtQQ1U0UAgYgZR3x+D1Mwo/y7Nd7fljxVYSpkdJR E7/+W/O1eu7eqKfe/eRfE9p4F9MWiNdIc5eWu4egE0EhnSqBbG9wS0v397SGpFd24xys xpOGyzy0FA+E+PCP3eLVeIyw9+SPQKkmlDdn6tJctEaP9yutUWYBUdFo8s5fLO1feTzf WjtLRuahNj+3Y6vpokGxF9hJDqXQ3yoar06wEc0I2NdWBNuIMmk1tnnEzCQvQvuVT/Je jiQRLVQ93Tl9/TGN1dKhK3W7x1gYjQtNUaDto9fS/g6wR1Voch85SaNNMPvqbGeaBEjP Bdmw== X-Gm-Message-State: AOAM530Su+WFRN413KeUEv9hw2yRjtJJ4dHSoQFVYg4xH2PCj96Jxhgj 4tiruWxveDvSH/yT/m/97LQ= X-Google-Smtp-Source: ABdhPJxusbb6FPJx4PIEbr3JmvscyUSXQq/YvxVnb07zp4qTjpOTaB5fhVZyCiTPd5pdBrjGnjdP7A== X-Received: by 2002:a05:620a:190b:: with SMTP id bj11mr29996853qkb.514.1636984616124; Mon, 15 Nov 2021 05:56:56 -0800 (PST) Received: from [192.168.2.100] (pool-72-79-19-93.nwrknj.east.verizon.net. [72.79.19.93]) by smtp.gmail.com with ESMTPSA id l2sm7702375qtk.41.2021.11.15.05.56.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Nov 2021 05:56:55 -0800 (PST) Content-Type: multipart/alternative; boundary="------------LlErI0JYQQUKUELdimzv4JYr" Message-ID: <17b31073-a676-9133-0219-4b2e42c347a4@gmail.com> Date: Mon, 15 Nov 2021 08:56:54 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.3.0 Subject: Re: postgresql13-llvm jit-13.5-1PGDG.rhel8.x86_64 Content-Language: en-US To: Pavel Stehule Cc: Pgsql Performance References: <86fccf60-1281-b81b-4c42-5a1ef8b032ab@gmail.com> From: Mladen Gogala In-Reply-To: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk This is a multi-part message in MIME format. --------------LlErI0JYQQUKUELdimzv4JYr Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11/15/21 00:04, Pavel Stehule wrote: > > Hi > > > There is a CentOS8-stream version which solves the problem but I > cannot > use that in the office. I will probably have to wait for another > month > before OL8 has everything that I need in its repositories. Now, the > question is what kind of an impact will running without llvm-jit > have? > According to the links below, llvm-jit effects are quite spectacular: > > https://llvm.org/devmtg/2016-09/slides/Melnik-PostgreSQLLLVM.pdf > > https://www.pgcon.org/2017/schedule/events/1092.en.html > > > When JIT was used on very large query with a lot of CASE expr, then > JIT has a positive effect about 50%. On usual large queries, the > effect of JIT was about 20%. Unfortunately, JIT is sensitive to > estimation, and the JIT sometimes increases seconds to queries, > although without JIT this query is executed in ms. When you use a > query that can be well calculated in parallel, then positive effect of > JIT is less. > > Regards > > Pavel Thanks Pavel, you answered my question. I'll wait with the upgrade. Regards -- Mladen Gogala Database Consultant Tel: (347) 321-1217 https://dbwhisperer.wordpress.com --------------LlErI0JYQQUKUELdimzv4JYr Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit


On 11/15/21 00:04, Pavel Stehule wrote:

Hi


There is a CentOS8-stream version which solves the problem but I cannot
use that in the office. I will probably have to wait for another month
before OL8 has everything that I need in its repositories. Now, the
question is what kind of an impact will running without llvm-jit have?
According to the links below, llvm-jit effects are quite spectacular:

https://llvm.org/devmtg/2016-09/slides/Melnik-PostgreSQLLLVM.pdf

https://www.pgcon.org/2017/schedule/events/1092.en.html

When JIT was used on very large query with a lot of CASE expr, then JIT has a positive effect about 50%. On usual large queries, the effect of JIT was about 20%. Unfortunately, JIT is sensitive to estimation, and the JIT sometimes increases seconds to queries, although without JIT this query is executed in ms. When you use a query that can be well calculated in parallel, then positive effect of JIT is less.

Regards

Pavel

Thanks Pavel, you answered my question. I'll wait with the upgrade.

Regards

-- 

Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com
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