Received: from malur.postgresql.org ([2a02:16a8:dc51::56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fhONu-0007Eu-Ut for pgsql-performance@arkaria.postgresql.org; Mon, 23 Jul 2018 00:07:31 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1fhONt-0001Ey-Bm for pgsql-performance@arkaria.postgresql.org; Mon, 23 Jul 2018 00:07:29 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fhONt-0001El-0Z for pgsql-performance@lists.postgresql.org; Mon, 23 Jul 2018 00:07:29 +0000 Received: from cat-porwal-prod-mail1.catalyst.net.nz ([202.78.240.226]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fhONo-00034d-2n for pgsql-performance@lists.postgresql.org; Mon, 23 Jul 2018 00:07:26 +0000 Authentication-Results: auth=pass smtp.auth=mark.kirkwood@catalyst.net.nz smtp.mailfrom=mark.kirkwood@catalyst.net.nz Received: from [IPv6:2406:e001:cf9:1:5b1:32e6:9b17:9ad] (unknown [IPv6:2406:e001:cf9:1:5b1:32e6:9b17:9ad]) (Authenticated sender: mark.kirkwood@catalyst.net.nz) by cat-porwal-prod-mail1.catalyst.net.nz (Postfix) with ESMTPSA id 4604080539; Mon, 23 Jul 2018 12:07:17 +1200 (NZST) Subject: Re: Why HDD performance is better than SSD in this case To: Neto pr Cc: Fabio Pardi , pgsql-performance@lists.postgresql.org References: <01bbbc88-2a47-f078-ea40-ab2c1acafa1f@portavita.eu> <4ae07b23-912b-e3fb-8e9a-2959c2a64f19@catalyst.net.nz> From: Mark Kirkwood Message-ID: Date: Mon, 23 Jul 2018 12:07:16 +1200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk Hi Neto, In a great piece of timing my new experimental SSD arrived (WD Black 500 G 3D NAND MVME) [1]. Doing some runs of query 9: - default config: 7 minutes - work_mem=1G, max_parallel_workers_per_gather=4: 3-4 minutes Increasing either of these much more got me OOM errors (16 G of ram). Anyway, enjoy your benchmarking! Cheers Mark [1] Yeah - I know this is a 'do not use me in production' type of SSD. It is however fine for prototyping and DSS scenario run type use. On 20/07/18 12:52, Neto pr wrote: > > Mark, > This query 9 is very hard, see my results for other queries (attached > - test with secondary index and without secondary index - only primary > keys), the SSD always wins in performance. > Only for this query that he was the loser, so I put this topic in the list. > > Today I will not be able to check your test information in more > detail, but I will return with more information soon. > > Best Regards > Neto > > > > >