Re: Re: [ADMIN] v7.1b4 bad performance - Mailing list pgsql-hackers

I wrote:
> 
> I tried with -B 1024 10 times for commit_delay=0 and 1 respectively.
> The average result of 'pgbench -c 10 -t 100' is as follows.
> 
> [commit_delay=0]
>  26.462817(including connections establishing)
>  26.788047(excluding connections establishing)
> [commit_delay=1]
>  27.630405(including connections establishing)
>  28.042666(excluding connections establishing)
> 

I got another clear result by simplifying pgbench.

[commit_delay = 0]
1)tps = 52.682295(including connections establishing) tps = 53.574140(excluding connections establishing)
2)tps = 54.580892(including connections establishing) tps = 55.672988(excluding connections establishing)
3)tps = 60.409452(including connections establishing) tps = 61.740995(excluding connections establishing)
4)tps = 60.787502(including connections establishing) tps = 62.131317(excluding connections establishing)
5)tps = 60.968409(including connections establishing) tps = 62.328142(excluding connections establishing)
6)tps = 62.396566(including connections establishing) tps = 63.614357(excluding connections establishing)
7)tps = 52.720152(including connections establishing) tps = 54.811739(excluding connections establishing)
8)tps = 53.417274(including connections establishing) tps = 54.454355(excluding connections establishing)
9)tps = 54.862412(including connections establishing) tps = 55.953512(excluding connections establishing)
10)tps = 60.616255(including connections establishing)  tps = 63.423590(excluding connections establishing)

[commit_delay = 1]
1)tps = 68.458715(including connections establishing) tps = 71.147012(excluding connections establishing)
2)tps = 71.059064(including connections establishing) tps = 72.685829(excluding connections establishing)
3)tps = 67.625556(including connections establishing) tps = 69.288699(excluding connections establishing)
4)tps = 84.749505(including connections establishing) tps = 87.430563(excluding connections establishing)
5)tps = 83.001418(including connections establishing) tps = 85.525377(excluding connections establishing)
6)tps = 66.235768(including connections establishing) tps = 67.830999(excluding connections establishing)
7)tps = 80.993308(including connections establishing) tps = 87.333491(excluding connections establishing)
8)tps = 69.844893(including connections establishing) tps = 71.640972(excluding connections establishing)
9)tps = 71.135311(including connections establishing) tps = 72.979021(excluding connections establishing)
10)tps = 68.091439(including connections establishing)  tps = 69.539728(excluding connections establishing)

The patch to let pgbench execute 1 query/trans is the following.

Index: pgbench.c
===================================================================
RCS file: /home/cvs/pgcurrent/contrib/pgbench/pgbench.c,v
retrieving revision 1.1
diff -c -r1.1 pgbench.c
*** pgbench.c    2001/02/20 07:55:21    1.1
--- pgbench.c    2001/02/22 10:03:52
***************
*** 217,222 ****
--- 217,224 ----             st->state = 0;     } 
+ if (st->state > 1)
+ st->state=6;     switch (st->state)     {         case 0:            /* about to start */

Regards,
Hiroshi Inoue