Bruce Momjian <pgman@candle.pha.pa.us> writes:
> But the snapshots only are grabbing the xids from each proc, right?
> Doesn't seem that would take very long.
Yeah, we've never seen any previous indication that grabbing a snapshot
is a bottleneck. Also, I think it uses a shared (read) lock, so there
shouldn't really be contention, unless perhaps they are starting and
stopping backends very frequently as well.
> If this is the bottleneck, maybe we need a shared proc lock.
We need to understand what's happening before speculating about how to
fix it ...
regards, tom lane