On Wed, Sep 21, 2016 at 8:47 AM, Dilip Kumar <dilipbal...@gmail.com> wrote: > Summary: > -------------- > At 32 clients no gain, I think at this workload Clog Lock is not a problem. > At 64 Clients we can see ~10% gain with simple update and ~5% with TPCB. > At 128 Clients we can see > 50% gain. > > Currently I have tested with synchronous commit=off, later I can try > with on. I can also test at 80 client, I think we will see some > significant gain at this client count also, but as of now I haven't > yet tested. > > With above results, what we think ? should we continue our testing ?
I have done further testing with on TPCB workload to see the impact on performance gain by increasing scale factor. Again at 32 client there is no gain, but at 64 client gain is 12% and at 128 client it's 75%, it shows that improvement with group lock is better at higher scale factor (at 300 scale factor gain was 5% at 64 client and 50% at 128 clients). 8 socket machine (kernel 3.10) 10 min run(median of 3 run) synchronous_commit=off scal factor = 1000 share buffer= 40GB Test results: ---------------- client head group lock 32 27496 27178 64 31275 35205 128 20656 34490 LWLOCK_STATS approx. block count on ClogControl Lock ("lwlock main 11") -------------------------------------------------------------------------------------------------------- client head group lock 32 80000 60000 64 150000 100000 128 140000 70000 Note: These are approx. block count, I have detailed result of LWLOCK_STAT, incase someone wants to look into. LWLOCK_STATS shows that ClogControl lock block count reduced by 25% at 32 client, 33% at 64 client and 50% at 128 client. Conclusion: 1. I think both LWLOCK_STATS and performance data shows that we get significant contention reduction on ClogControlLock with the patch. 2. It also shows that though we are not seeing any performance gain at 32 clients, but there is contention reduction with patch. I am planning to do some more test with higher scale factor (3000 or more). -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers