Amit-san, On Wed, Mar 20, 2019 at 9:07 AM, Amit Langote wrote: > On 2019/03/20 17:36, Imai, Yoshikazu wrote: > > On Wed, Mar 20, 2019 at 8:21 AM, Amit Langote wrote: > >> On 2019/03/20 12:15, Imai, Yoshikazu wrote: > >>> [select1024.sql] > >>> \set a random (1, 1024) > >>> select * from rt where a = :a; > >>> > >>> [pgbench] > >>> pgbench -n -f select1024.sql -T 60 > >> > >> Thank you. > >> > >> Could you please try with running pgbench for a bit longer than 60 > seconds? > > > > I run pgbench for 180 seconds but there are still difference. > > Thank you very much. > > > 1024: 7,004 TPS > > 8192: 5,859 TPS > > > > > > I also tested for another number of partitions by running pgbench for > 60 seconds. > > > > num of part TPS > > ----------- ----- > > 128 7,579 > > 256 7,528 > > 512 7,512 > > 1024 7,257 (7274, 7246, 7252) > > 2048 6,718 (6627, 6780, 6747) > > 4096 6,472 (6434, 6565, 6416) (quoted from above (3)'s results) > > 8192 6,008 (6018, 5999, 6007) > > > > > > I checked whether there are the process which go through the number > of partitions, but I couldn't find. I'm really wondering why this > degradation happens. > > Indeed, it's quite puzzling why. Will look into this.
I don't know whether it is useful, but I noticed the usage of get_tabstat_entry increased when many partitions are scanned. -- Yoshikazu Imai