Re: [HACKERS] wait events for disk I/O

On Wed, Mar 8, 2017 at 4:50 PM, Rushabh Lathia <rushabh.lathia@gmail.com> wrote:

I am attaching  another version of the patch, as I found stupid mistake

in the earlier version of patch, where I missed to initialize initial value to
WaitEventIO enum. Also earlier version was not getting cleanly apply on
the current version of sources.

I have applied attached patch, set shared_buffers to 128kB and ran pgbench, I am able to see below distinct IO events.

--with ./pgbench -i -s 500 postgres
application_name    wait_event_type    wait_event              query
 pgbench                  IO                          ExtendDataBlock   copy pgbench_account
 pgbench                  IO                          WriteXLog              copy pgbench_account
 pgbench                  IO                          WriteDataBlock      copy pgbench_account
 pgbench                  IO                          ReadDataBlock      vacuum analyze pgben
 pgbench                  IO                          ReadBuffile            alter table pgbench_

--with ./pgbench -T 600 postgres (readwrite)
application_name    wait_event_type    wait_event              query
 pgbench                 IO                           ReadDataBlock      UPDATE pgbench_accou
 pgbench                 IO                           WriteDataBlock      UPDATE pgbench_telle
                                IO                           SyncDataBlock    
 pgbench                 IO                           SyncDataBlock      UPDATE pgbench_telle
                                IO                           SyncDataBlock      autovacuum: VACUUM A
 pgbench                 IO                           WriteXLog              END;
 pgbench                 IO                           ExtendDataBlock   copy pgbench_account

--with ./pgbench -T 600 -S postgres (select only)
application_name    wait_event_type    wait_event              query
 pgbench                 IO                           ReadDataBlock      SELECT abalance FROM

Attached excel with all IO event values.

Thanks & Regards,

Rajkumar Raghuwanshi

QMG, EnterpriseDB Corporation