On Mon, Oct 31, 2016 at 7:02 PM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > > The remaining benchmark with 512 clog buffers completed, and the impact > roughly matches Dilip's benchmark - that is, increasing the number of clog > buffers eliminates all positive impact of the patches observed on 128 > buffers. Compare these two reports: > > [a] http://tvondra.bitbucket.org/#pgbench-3000-logged-sync-noskip-retest > > [b] http://tvondra.bitbucket.org/#pgbench-3000-logged-sync-noskip-retest-512 > > With 128 buffers the group_update and granular_locking patches achieve up to > 50k tps, while master and no_content_lock do ~30k tps. After increasing > number of clog buffers, we get only ~30k in all cases. > > I'm not sure what's causing this, whether we're hitting limits of the simple > LRU cache used for clog buffers, or something else. >
I have also seen previously that increasing clog buffers to 256 can impact performance negatively. So, probably here the gains due to group_update patch is negated due to the impact of increasing clog buffers. I am not sure if it is good idea to see the impact of increasing clog buffers along with this patch. -- With Regards, Amit Kapila. 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
