On 10/12/13 13:14, Mark Kirkwood wrote:
On 10/12/13 12:14, Heikki Linnakangas wrote:
I took a stab at using posix_fadvise() in ANALYZE. It turned out to
be very easy, patch attached. Your mileage may vary, but I'm seeing a
nice gain from this on my laptop. Taking a 30000 page sample of a
table with 717717 pages (ie. slightly larger than RAM), ANALYZE takes
about 6 seconds without the patch, and less than a second with the
patch, with effective_io_concurrency=10. If anyone with a good test
data set loaded would like to test this and post some numbers, that
would be great.
I did a test run:
pgbench scale 2000 (pgbench_accounts approx 25GB).
postgres 9.4
i7 3.5Ghz Cpu
16GB Ram
500 GB Velociraptor 10K
(cold os and pg cache both runs)
Without patch: ANALYZE pgbench_accounts 90s
With patch: ANALYZE pgbench_accounts 91s
So I'm essentially seeing no difference :-(
Arrg - sorry forgot the important bits:
Ubuntu 13.10 (kernel 3.11.0-14)
filesystem is ext4
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