Re: AIO v2.5

Hi,

I kept running the tests on additional storage systems, both "local"
(e.g. RAID on SATA SSDs) and "cloud" (Azure Premium SSD volumes). And
also on FreeBSD/ZFS, to see what non-Linux systems do. I pushed all the
results to the same github repository, into separate branches.

I'm attaching three example charts, from these "new" systems.

In general, it doesn't change the earlier conclusions at all. Most of
the earlier observations apply to these results from these machines with
reasonably different types of storage. So I still think we should stick
to "worker", but consider increasing the default number of workers.

It's possible there's machine with storage/hardware that would work
better with some other io_method value, but that's why it's a GUC. The
default should work for most systems.

I plan to let the current tests complete, but that's about it. I don't
plan to test additional systems for this thread. I'll keep running tests
for the index-prefetch thread, but that's focused on other questions.

regards

--
Tomas Vondra