Re: scaling multiple connections

At 08:39 AM 26-04-2001 -0400, mlw wrote:
>I am getting a bit concerned about Postgres 7.1 performance with multiple
>connections. Postgres does not seem to scaling very well. Below there is a
list
>of outputs from pgbench with different number of clients, you will see that
>
>My postmaster start line looks like:
>/usr/local/pgsql/bin/postmaster -A0 -N 24 -B 4096 -i -S -D/sqlvol/pgdev -o -F
>-fs -S 2048

Maybe it's the -fs in your start up line.

I tried a similar start line as yours but without -fs and I get consistent
tps values for pgbench.

./pgbench -v -c 1 -t 30 test
starting vacuum...end.
starting full vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 1
number of transactions per client: 30
number of transactions actually processed: 30/30
tps = 161.938949(including connections establishing)
tps = 180.060140(excluding connections establishing)
[lylyeoh(at)nimbus pgbench]$ ./pgbench -v -c 3 -t 30 test
starting vacuum...end.
starting full vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 3
number of transactions per client: 30
number of transactions actually processed: 90/90
tps = 172.909666(including connections establishing)
tps = 189.845782(excluding connections establishing)
[lylyeoh(at)nimbus pgbench]$ ./pgbench -v -c 4 -t 30 test
starting vacuum...end.
starting full vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 4
number of transactions per client: 30
number of transactions actually processed: 120/120
tps = 172.909417(including connections establishing)
tps = 189.319538(excluding connections establishing)

Tested machine is a Dell Poweredge 1300 uniprocessor PIII 500MHz with 128MB
RAM, and a single 9GB HDD.

With -fs there's a decrease, but not as marked as your case. So not sure if
it's really the problem.

Try that out.

Cheerio,
Link.