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[86.49.250.165]) by smtp.gmail.com with ESMTPSA id o5-20020a170906974500b006dfc781498dsm13383478ejy.37.2022.04.12.08.40.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 12 Apr 2022 08:40:59 -0700 (PDT) Message-ID: <03cf0942-662b-8ef5-90e4-b8182f2e1b8d@enterprisedb.com> Date: Tue, 12 Apr 2022 17:41:00 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: WIP: WAL prefetch (another approach) Content-Language: en-US To: Simon Riggs , Thomas Munro Cc: Julien Rouhaud , Ashutosh Sharma , Daniel Gustafsson , Stephen Frost , Alvaro Herrera , Andres Freund , David Steele , Dmitry Dolgov <9erthalion6@gmail.com>, Jakub Wartak , Tom Lane , Tomas Vondra , pgsql-hackers References: <20220309064633.woyf53w3odnhltah@jrouhaud> <20220311082737.bmnlmtzwi2xqrhxl@jrouhaud> <20220314071713.v4anmngdi5njaple@jrouhaud> <20220321082916.ysrlw2xst2tpyc5a@jrouhaud> From: Tomas Vondra In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CLOUD-SEC-AV-Info: enterprisedb,google_mail,monitor X-CLOUD-SEC-AV-Sent: true X-Gm-Spam: 0 X-Gm-Phishy: 0 List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk On 4/12/22 15:58, Simon Riggs wrote: > On Thu, 7 Apr 2022 at 08:46, Thomas Munro wrote: > >> With that... I've finally pushed the 0002 patch and will be watching >> the build farm. > > This is a nice feature if it is safe to turn off full_page_writes. > > When is it safe to do that? On which platform? > > I am not aware of any released software that allows full_page_writes > to be safely disabled. Perhaps something has been released recently > that allows this? I think we have substantial documentation about > safety of other settings, so we should carefully document things here > also. > I don't see why/how would an async prefetch make FPW unnecessary. Did anyone claim that be the case? regards -- Tomas Vondra EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company