Hi,
On 2022-11-24 10:43:46 +0530, Bharath Rupireddy wrote:
> While working on something else, I noticed that the proc array group
> XID clearing leader resets procArrayGroupNext of all the followers
> atomically along with procArrayGroupMember. ISTM that it's enough for
> the followers to exit the wait loop and continue if the leader resets
> just procArrayGroupMember, the followers can reset procArrayGroupNext
> by themselves. This relieves the leader a bit, especially when there
> are many followers, as it avoids a bunch of atomic writes and
> pg_write_barrier() for the leader .
I doubt this is a useful change - the leader already has to modify the
relevant cacheline (for procArrayGroupMember). That makes it pretty much free
to modify another field in the same cacheline.
Greetings,
Andres Freund