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 1lRXRm-0005YZ-9u for pgsql-admin@arkaria.postgresql.org; Wed, 31 Mar 2021 09:47:34 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1lRXRl-00020O-8U for pgsql-admin@arkaria.postgresql.org; Wed, 31 Mar 2021 09:47:33 +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 1lRXRl-00020H-1T for pgsql-admin@lists.postgresql.org; Wed, 31 Mar 2021 09:47:33 +0000 Received: from mail-ej1-x631.google.com ([2a00:1450:4864:20::631]) by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1lRXRi-0005Y5-IM for pgsql-admin@lists.postgresql.org; Wed, 31 Mar 2021 09:47:31 +0000 Received: by mail-ej1-x631.google.com with SMTP id ce10so29128180ejb.6 for ; Wed, 31 Mar 2021 02:47:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cybertec-at.20150623.gappssmtp.com; s=20150623; h=message-id:subject:from:to:date:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=O+W/VLzcQIITf75Ahrk6w55Y25D3JwsCXMGn65GxYuw=; b=oUSiMfkCC/Gx5l032u5XuchWEBXEiM9kILIfrmUwGsIrgUOq+X2r527HBF7CqGX8kA QMG32BgXdtz0lvW+PJpdTLmOc9z00FfAci9h6LdxhR9Q5vm+vPIJ5nYknIaFsy5F22Fv bpF8xSLH5X4jhGMFby7s1gS+UtKrokkSViM1I36Hk6eAdKO/drvrMU+0QtZyJ4Jbo0BR vzQfoMinjlkyqY74czbf9WP+eGecdNsTVIP+x28CniRuKH+3hLlXlb8Xz9GDWATqIfDE CRzRQCH54gBp8IhAsN0ovRAV7rOliegeDzSjKAAizOEpRJQnjgJ6OXjxntRAJu7wORmO lGVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:date:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=O+W/VLzcQIITf75Ahrk6w55Y25D3JwsCXMGn65GxYuw=; b=ePmiPp/zh3OTZcXR9glPHP1iIliXYTvFSU7lR3HUnisxtbjvrt2kfrcflEXugx68nz V21qN+seePKtZ31Q6ybmctBnGRFAPdt2l2jw+pLaAbMEGU+PBhsOqb24cDuybB5LXbSw UlkPE3BOGG2gqTsei5Zb9AwKfUjjmWy6cI9vlcqAss5k7jEet43JU7v3wtKwt7dg/RXO W6FHwZmtSqe6/CYugfInN+iIMdPpM7INmK4rL31wNwmDyUrRcR33adPBOv0Zy2BEa9P4 iDDPCM55GeRzglq28Whgkwa4BdFi96X/r5I+TYIG/OB3OmGCynaB1/uGsMT1aEj0iyTu wgVw== X-Gm-Message-State: AOAM531jIB62ZQLeNIKarx46w5l32TbiuuT9h9Pye7Go63R3PjPcwFUE 5EKVN4z4BjYhOAiTyApQ1nM92NoxV/SNWA== X-Google-Smtp-Source: ABdhPJyjs4KPy59sv2naDz38IteHg9Wf7NS65I2EDuT3H3Ry5zHpuUn2M7V+TR7Gm/ZTqS1iBUJ3Rw== X-Received: by 2002:a17:906:9442:: with SMTP id z2mr2717403ejx.79.1617184049208; Wed, 31 Mar 2021 02:47:29 -0700 (PDT) Received: from localhost.localdomain (217-149-171-113.nat.highway.telekom.at. [217.149.171.113]) by smtp.gmail.com with ESMTPSA id i1sm846058ejh.94.2021.03.31.02.47.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Mar 2021 02:47:28 -0700 (PDT) Message-ID: <11921e4e3efa7782168b8e02b89d004ba5b6b00a.camel@cybertec.at> Subject: Re: Performance bottleneck. High active sessions but postmaster kernel threads are in a sleep state, low CPU utilization From: Laurenz Albe To: Hotmail , pgsql-admin@lists.postgresql.org Date: Wed, 31 Mar 2021 11:47:28 +0200 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk On Tue, 2021-03-30 at 12:22 -0600, Hotmail wrote: > We are trying to gain some insight into a performance bottleneck that we are hitting while load testing Postgres on 11.11. > [hundreds of active sessions, but CPU is not maxed out] With that many active sessions you are probably hitting some contention inside the database. Look at "wait_event" and "wait_event_type" in pg_stat_activity. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com