Hello Raymond,
>> Note that this does not mean that the patch should not be applied, it
>> looks like an oversight, but really I do not have the performance
>> degradation you are suggesting.
>
> I appreciate your input and I want to come up with a canonical test that
> makes this contention more obvious. Unfortunately, it is difficult
> because the criteria that causes this slow down (large query sizes and
> distinct non-repeated queries) are difficult to reproduce with pgbench.
> I would be open to any suggestions here.
>
> So even though the performance gains in this specific scenario are not
> as great, do you still think it would make sense to submit a patch like
> this?
Sure, it definitely makes sense to reduce the overhead when the extension
is disabled. I wanted to understand the source of performance issue, and
your explanations where not enough for reproducing it.
--
Fabien.