On Thu, Apr 30, 2020 at 4:15 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Wed, Apr 29, 2020 at 6:11 PM Suraj Kharage > <suraj.khar...@enterprisedb.com> wrote: > > > > Hi, > > > > We at EnterpriseDB did some performance testing around this parallel backup > > to check how this is beneficial and below are the results. In this testing, > > we run the backup - > > 1) Without Asif’s patch > > 2) With Asif’s patch and combination of workers 1,2,4,8. > > > > We run those test on two setup > > > > 1) Client and Server both on the same machine (Local backups) > > > > 2) Client and server on a different machine (remote backups) > > > > > > Machine details: > > > > 1: Server (on which local backups performed and used as server for remote > > backups) > > > > 2: Client (Used as a client for remote backups) > > > > > ... > > > > > > Client & Server on the same machine, the result shows around 50% > > improvement in parallel run with worker 4 and 8. We don’t see the huge > > performance improvement with more workers been added. > > > > > > Whereas, when the client and server on a different machine, we don’t see > > any major benefit in performance. This testing result matches the testing > > results posted by David Zhang up thread. > > > > > > > > We ran the test for 100GB backup with parallel worker 4 to see the CPU > > usage and other information. What we noticed is that server is consuming > > the CPU almost 100% whole the time and pg_stat_activity shows that server > > is busy with ClientWrite most of the time. > > > > > > Was this for a setup where the client and server were on the same > machine or where the client was on a different machine? If it was for > the case where both are on the same machine, then ideally, we should > see ClientRead events in a similar proportion? >
During an offlist discussion with Robert, he pointed out that current basebackup's code doesn't account for the wait event for the reading of files which can change what pg_stat_activity shows? Can you please apply his latest patch to improve basebackup.c's code [1] which will take care of that waitevent before getting the data again? [1] - https://www.postgresql.org/message-id/CA%2BTgmobBw-3573vMosGj06r72ajHsYeKtksT_oTxH8XvTL7DxA%40mail.gmail.com -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
