Re: Speed up pg_checksums in cases where checksum already set

On Thu, May 27, 2021 at 5:24 AM Greg Sabino Mullane <htamfids(at)gmail(dot)com> wrote:
>
> The attached patch makes an optimization to pg_checksums which prevents rewriting the block if the checksum is already what 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 data directory 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.