How to increase the connection throughput for pgbouncer?

Question

I am using pgbouncer in transaction mode & trying to allow close to 500 active transaction. The purpose is simply to stress test the setup

Current setup: [ \'n\'

Answer 1

If you are running PgBouncer on the same host as PostgreSQL, you should increase CPU priority of pgbouncer process with renice.

renice -10 -p `pidof pgbouncer`

Default Linux scheduler is round-robin and it starves PgBouncer because it treats all processes equally - and hundreds of postgres processes overwhelm single pgbouncer process.

It's usually not a problem under moderate load, but it can be a really important factor when running lots of small transactions.

Even renice cannot do magic: if you run more than 10k+ TPS, you probably have to consider some load balancing (HAProxy?) in front of (multiple) PgBouncer.