Re: Speed up pg_checksums in cases where checksum already set - Mailing list pgsql-hackers

From Julien Rouhaud
Subject Re: Speed up pg_checksums in cases where checksum already set
Date
Msg-id CAOBaU_bT0_U8j_dim5NtOPSmMDRS0jvxvt8PMjA_DcCZLK8BhQ@mail.gmail.com
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In response to Speed up pg_checksums in cases where checksum already set  (Greg Sabino Mullane <htamfids@gmail.com>)
List pgsql-hackers
On Thu, May 27, 2021 at 5:24 AM Greg Sabino Mullane <htamfids@gmail.com> wrote:
>
> The attached patch makes an optimization to pg_checksums which prevents rewriting the block if the checksum is
alreadywhat we expect. This can lead to much faster runs in cases where it is already set (e.g. enabled -> disabled ->
enable,external helper process, interrupted runs, future parallel processes). There is also an effort to not sync the
datadirectory if no changes were written. Finally, added a bit more output on how many files were actually changed,
e.g.:

I don't know how often this will actually help as probably people
aren't toggling the checksum state that often, but it seems like a
good idea overall.  The patch looks sensible to me.



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