Re: pgbench: option delaying queries till connections establishment?

>
> I've recently run into something I am having difficulty understanding.
>
> I am running pgbench with the following
> pgbench -h localhost -c 100 -j 100 -t 2 -S -s 1000 pgbench -U pgbench
> --protocol=simple
>
> Without pgbouncer I get around 5k TPS
> with pgbouncer I get around 15k TPS
>
> Looking at the code connection initiation time should not be part of the
> calculation so I' puzzled why pgbouncer is making such a dramatic
> difference ?
>
> Dave
>

Turns out that for this specific test, pg is faster with a pooler.

Dave Cramer, [May 16, 2023 at 9:49:24 AM]:

turns out having a connection pool helps. First run is without a pool,
second with

pgbench=# select mean_exec_time, stddev_exec_time, calls, total_exec_time,
min_exec_time, max_exec_time from pg_stat_statements where
queryid=-531095336438083412;

mean_exec_time | stddev_exec_time | calls | total_exec_time |
min_exec_time
| max_exec_time

--------------------+--------------------+-------+-------------------+----------------------+---------------

0.4672699999999998 | 2.2758508661446535 | 200 | 93.45399999999997 |
0.046616000000000005 | 17.434766

(1 row)

pgbench=# select pg_stat_statements_reset();

pg_stat_statements_reset

--------------------------

(1 row)

pgbench=# select mean_exec_time, stddev_exec_time, calls, total_exec_time,
min_exec_time, max_exec_time from pg_stat_statements where
queryid=-531095336438083412;

mean_exec_time | stddev_exec_time | calls | total_exec_time |
min_exec_time | max_exec_time

---------------------+----------------------+-------+--------------------+---------------+---------------

0.06640186499999999 | 0.021800404695481574 | 200 | 13.280373000000004 |
0.034006 | 0.226696
(1 row)