Re: pgbench unable to scale beyond 100 concurrent connections

Hello Sachin,

Your report is very imprecise so it is hard to tell anything.

What version of client and server are you running? On what hardware ? (200
connections => 200 active postgres processes, how many processes per core
are you expecting to run? the recommanded value is about 2 connections per
physical core...) What precise command is started? How to you know it
"comes down to 100 connections"? Are there error messages from pgbench or
postgresql?

My random guess would be that you start too many connections with only one
thread client side and/or on a too small hardware client or server-side
for the expected scale, so given the load and latency some connections
just never get to do anything?

Maybe try with "-j 20" so that there are not too many connections per
pgbench thread?

> I am testing pgbench with more than 100 connections. also set
> max_connection in postgresql.conf more than 100.
>
> Initially pgbench tries to scale nearby 150 but later it come down to 100
> connections and stable there.
>
> It this limitation of pgbench? or bug? or i am doing it wrong way?
>
> ---
> I tested it with max_connection = 200 in postgresql.conf
> and pgbench witn -c 180/190/200

> Please reply.

Please send precise information instead of expecting people to guess...

--
Fabien