Why pgpool TPS is lowest versus postgresql direct connections?

["Lazaro Garcia" <lazaro3487@xxxxxxxxx>]

The correct results reported by sysbench was:

 

Concurrent Users	1	20	50	100
PostgreSQL	3582	11943	12852	10618
Pgpool	2240	7628	7013	6135

 

Is there any way to tuning this behavior?

 

Regards

 

 

De: Lazaro Garcia [mailto:lazaro3487@xxxxxxxxx]
Enviado el: miércoles, 8 de febrero de 2017 05:28 p. m.
Para: 'pgpool-general@xxxxxxxxxx'; 'pgsql-admin@xxxxxxxxxxxxxx'
Asunto: Why pgpool TPS is lowest versus postgresql direct connections?

 

After installed Pgpool with 2 postgresql nodes with streaming replication, I have noticed that access directly to postgresql is more efficient than through pgpool.

 

I supposed that load balance could increase the transactions per second executed because each node could receive more load, but the results shown below are not expected.

 

This is the setup:

 

Pgpool 3.6.1 whit connection pooling, streaming replication mode and load balancing mode.

 

2 PostgreSQL server 9.6.1 whit streaming replication.

 

For the tests I used sysbench and pgbench.

 

The results of sysbench:

 

Concurrent Users	1	20	50	100
PostgreSQL (TPS) Direct	1166	20936	25743	27344
Pgpool (TPS)	2240	7628	7013	6135

 

 

The results of pgbench

 

	1	20	50	100
PostgreSQL (TPS) Direct	1403	6805	6194	5726
Pgpool (TPS)	511	5430	5528	4705

 

 

As you can see in both cases even with load balance, the total transactions per second are lower.

 

Is this the expected behavior. Is there any way to allow more TPS when pgpool is used?

 

There are other publications with similar results:

 

https://www.os3.nl/_media/2011-2012/courses/lia/rory_breuk_gerrie_veerman_-_report.pdf    (page 28)

http://www.mail-archive.com/pgpool-general@xxxxxxxxxxxxx/msg03326.html

 

 

Regards