On December 7, 2018 11:56:55 AM PST, Alvaro Herrera <alvhe...@2ndquadrant.com>
wrote:
>BTW, a couple of months ago I measured the performance implications for
>a single update under pgbench and it represented a decrease of about
>3%-5%. Side-effects such as xid consumption have worse implications,
>but as far as performance is concerned, it's not as bad as all that.
I don't think that's a fair test for the performance downsides. For pgbench
with modifications the full commit is such a large portion of the time that
you'd need to make things a lot slower to show a large slowdown. And for ro
pgbench the subxacts don't matter that much. It'd probably be more meaningful
to have a mixed workload of 15 ro statements per xact in one type of session,
and 5rw /10ro in another.
Andres
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