[Pgpool-general] pgpool II performance

[Jay Payne]

Thank you for your reply.   I have done some further tests:

Taking into account possible network problems I ran pgbench on the pgpool
server hitting the db server directly to gauge any network latency issues:

postgres at db-2:~$ pgbench -c 20 -t 1000 -h XX.XXX.XX.XXX -p 5432 testdb1
starting vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 20
number of transactions per client: 1000
number of transactions actually processed: 20000/20000
tps = 974.866385 (including connections establishing)
tps = 977.606505 (excluding connections establishing)

turning off replication and only using pgpool "connection pooling" I still
get a pretty big decrease in performance.
postgres at db-2:~$ pgbench -c 20 -t 1000 -h localhost -p 9999 testdb
starting vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 20
number of transactions per client: 1000
number of transactions actually processed: 20000/20000
tps = 718.794739 (including connections establishing)
tps = 742.188834 (excluding connections establishing)


I still think I might have something configured incorrectly.   Is pgbench
not a good tool to benchmark the connection pooling with?


Thank you for your time.

--J
On Thu, Mar 6, 2008 at 10:46 PM, Tatsuo Ishii <ishii at sraoss.co.jp> wrote:

> > I'm running Postgres 8.1.11.   Here are the results of a pgbench test
> > pgbench -c 20 -t 1000 testdb
> > starting vacuum...end.
> > transaction type: TPC-B (sort of)
> > scaling factor: 1
> > number of clients: 20
> > number of transactions per client: 1000
> > number of transactions actually processed: 20000/20000
> > tps = 731.350579 (including connections establishing)
> > tps = 732.860160 (excluding connections establishing)
> >
> > I set up another environment with 3 servers 1 pgpool server and 2
> masters
> > for master-master replication.  Everything on the pgpool functions great
> but
> > the performance is terrible.   Here are the results of the same pgbench
> test
> > run on the pgpool cluster.
> > pgbench -p 9999 -c 20 -t 1000 testdb
> > starting vacuum...end.
> > transaction type: TPC-B (sort of)
> > scaling factor: 1
> > number of clients: 20
> > number of transactions per client: 1000
> > number of transactions actually processed: 20000/20000
> > tps = 443.242941 (including connections establishing)
> > tps = 443.912381 (excluding connections establishing)
> > tps = 401.669441 (excluding connections establishing)
> >
> >
> > All four servers have exactly the same hardware configuration.
> >
> > Is this performance loss normal?
>
> Yes.
>
> I think existing shared-nothing-synchronous-replication softwares
> including PGCluster will show more or less same performance.
>
> I should note that while other such replication softwares show the
> performance degration almost propotional to the numbers of PostgreSQL
> servers, pgpool's performance is not worse than 1/2 of PostgreSQL.
>
> Also please note that READ query performance will increase according
> to the numbers of PostgreSQL servers. So you have a chance to get
> performance boost if most of your quries are READ. Of course this may
> vary to the characteristics of load though.
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
>
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