On 29 June 2016 at 18:47, Sachin Kotwal <kotsac...@gmail.com> wrote:
> 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? > What makes you think this is a pgbench limitation? It sounds like you're benchmarking the client and server on the same system. Couldn't this be a limitation of the backend PostgreSQL server? It also sounds like your method of counting concurrent connections is probably flawed. You're not allowing for setup and teardown time; if you want over 200 connections really running at very high rates of connection and disconnection you'll probably need to raise max_connections a bit to allow for the ones that're starting up or tearing down at any given time. Really, though, why would you want to do this? I can measure my car's speed falling off a cliff, but that's not a very interesting benchmark for a car. I can't imagine any sane use of the database this way, with incredibly rapid setup and teardown of lots of connections. Look into connection pooling, either client side or in a proxy like pgbouncer. -- Craig Ringer http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
