Heikki Linnakangas <heikki.linnakan...@enterprisedb.com> writes:
> Tom Lane wrote:
>> What if PREPARE simply didn't write the 2PC file at all, except into WAL?
> Interesting idea, might be worth performance testing. Peeking into the
> WAL files during normal operation feels naughty, but it should work.
> However, if the bottleneck is the WAL fsyncs, I doubt it's any faster
> than Michael's current patch.
This isn't about faster, it's about not requiring users to estimate
a suitable size for a shared-memory arena.
> Actually, it would be interesting to performance test a stripped down
> broken implementation that doesn't write the state files anywhere but
> WAL, PREPARE releases all locks like regular COMMIT does, and COMMIT
> PREPARED just writes the commit record and fsyncs. That would give an
> upper bound on how much gain any of these patches can have. If that's
> not much, we can throw in the towel.
Good idea --- although I would think that the performance of 2PC would
be pretty context-dependent anyway. What load would you test under?
regards, tom lane
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