Re: data-checksums

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От Stephen Frost
Тема Re: data-checksums
Дата
Msg-id 20180109175410.GH2416@tamriel.snowman.net
обсуждение исходный текст
Ответ на data-checksums  ("Rakesh Kumar" <rakeshkumar464@mail.com>)
Ответы Re: data-checksums  ("Rakesh Kumar" <rakeshkumar464@mail.com>)
Список pgsql-general
Greetings,

* Rakesh Kumar (rakeshkumar464@mail.com) wrote:
> --data-checksums
> Use checksums on data pages to help detect corruption by the I/O system that would otherwise be silent. Enabling
checksumsmay incur a noticeable performance penalty. This option can only be set during initialization, and cannot be
changedlater. If set, checksums are calculated for all objects, in all databases. 
> ====
>
> If I understand it correctly, the performance penalty is when the blocks are written to the disk by the background
writerand/or during checkpoint.  Given that the process is async and application does not wait on it, is the
performancepenalty really a big concern. 

There's also a hit when pages are read back in, since we need to
calculate the checksum and verify it hasn't changed.

That said, imv anyway, the performance hit is small and having checksums
is well worth it.

Thanks!

Stephen

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