Simon Riggs <simon@2ndquadrant.com> writes:
> As discussed in the other thread "Final Thoughts for 8.3 on LWLocking
> and Scalability", XidCacheRemoveRunningXids() is now the only holder of
> an X lock during normal processing,
Nonsense. Main transaction exit also takes an exclusive lock, and is
far more likely to be exercised in typical workloads than a
subtransaction abort.
In any case: there has still not been any evidence presented by anyone
that optimizing XidCacheRemoveRunningXids will help one bit. Given the
difficulty of measuring any benefit from the last couple of
optimizations in this general area, I'm thinking that such evidence
will be hard to come by. And we have got way more than enough on our
plates already. Can we let go of this for 8.3, please?
regards, tom lane