På tirsdag 09. januar 2018 kl. 21:37:16, skrev Joshua D. Drake < j...@commandprompt.com <mailto:j...@commandprompt.com>>: On 01/09/2018 12:22 PM, Andres Freund wrote: > On 2018-01-09 20:04:04 +0100, Rakesh Kumar wrote: >>>> I also would like to believe that the hit is small, but when PG >>>> official document writes "noticeable performance penalty", it becomes >>>> difficult to convince management that the hit is small :-) >>> Why believe, when you can measure? >> yup doing that. But I still feel that PG documentation should stay >> away from such scare mongering. Or did the lawyers write that :) > So we should rather lie about it having a potential for performance > impact? Who'd be helped by that?
It isn't a lie, it depends on the workload and hardware. Adjusting the documentation to say something like the following probably isn't a bad idea: The use of the data checksum feature may incur a performance penalty. However, this does depend on your particular workload and provisioned hardware. It is wise to test the feature based on your specific requirements. Does PG use HW-accellerated crc if CPU supports it[1]? [1] https://en.wikipedia.org/wiki/SSE4 -- Andreas Joseph Krogh CTO / Partner - Visena AS Mobile: +47 909 56 963 andr...@visena.com <mailto:andr...@visena.com> www.visena.com <https://www.visena.com> <https://www.visena.com>
