On Fri, Mar 4, 2016 at 7:11 PM, Alexander Korotkov <aekorotkov@gmail.com> wrote: > >> >> If yes, then the only slight worry is that there will lot of repetition in wait_event_type column, otherwise it is okay. > > > There is morerows attribute of entry tag in Docbook SGML, it behaves like rowspan in HTML. >
Thanks for the suggestion. I have updated the patch to include wait_event_type information in the wait_event table.
As asked above by Robert, below is performance data with the patch.
M/C Details
------------------
IBM POWER-8 24 cores, 192 hardware threads RAM = 492GB
The read-only data shows some improvement with patch, but I think this is mostly attributed to run-to-run variation.
pgbench read-write (median of 3, 30-min runs)
clients
BASE
PATCH
%
1
1703.275728
1696.568881
-0.3937616729
8
8884.406185
9442.387472
6.2804567394
64
32648.82798
32113.002416
-1.6411785572
In the above data, the read-write data shows small regression (1.6%) at higher client-count, but when I ran individually that test, the difference was 0.5%. I think it is mostly attributed to run-to-run variation as we see with read-only tests.
Thanks to Mithun C Y for doing performance testing of this patch.
As this patch is adding 4-byte variable to shared memory structure PGPROC, so this is susceptible to memory alignment issues for shared buffers as discussed in thread [1], but in general the performance data doesn't indicate any regression.