Re: Slow standby snapshot

On Wed, Nov 10, 2021 at 12:16 AM Michail Nikolaev
<michail.nikolaev@gmail.com> wrote:
> I updated the patch a little. KnownAssignedXidsGetAndSetXmin now
> causes fewer cache misses because some values are stored in variables
> (registers). I think it is better to not lean on the compiler here
> because of `volatile` args.
> Also, I have added some comments.

It looks like KnownAssignedXidsNext doesn't have to be
pg_atomic_uint32.  I see it only gets read with pg_atomic_read_u32()
and written with pg_atomic_write_u32().  Existing code believes that
read/write of 32-bit values is atomic.  So, you can use just uint32
instead of pg_atomic_uint32.

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Regards,
Alexander Korotkov