On 29 June 2016 at 21:49, Sachin Kotwal <kotsac...@gmail.com> wrote: > Hi, > > > On Wed, Jun 29, 2016 at 6:29 PM, Craig Ringer <cr...@2ndquadrant.com> > wrote: > >> 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? >> > > As I mentioned when I tried same thing with sysbench It can give me 200+ > concurrent connection with same method and same machine. >
What command lines / configs are you using? Details are necessary, talking about this in general hand-waving terms is not getting anywhere. > > >> 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? >> >> I think having client and server on same server should not be problem. > As i can do this with different benchmarking tool It should not be > limitation of backend PostgreSQL server. > OK, so your sysbench use is actually talking to PostgreSQL as well. Then yes. Assuming they're testing roughly the same thing, which I somewhat doubt. There should not be connection and disconnection because I am not using -C > option of pgbench which cause connection and disconnection for each query. > OK, in that case it's hard to explain the behaviour you're seeing. More details please. > If I set max_connection of postgresql.conf to 200 and testing with -c 150 . > This should work fine, but it is not. > If you're using FDWs to connect to the same server again, you'll need a max_connections slot for each FDW connection as well. > I am testing one scenario of multiple coordinator with help of > postgres_fdw to enhance connection ability of postgres without any > connection pooling . > Setup might be difficult to explain here but will explain if required. > Yes, you need to explain it. > can you test simply 100 scale database size with pgbench and run pgbench > with 200+ connection of small virtual box to see same observation ? > It works fine - of course. There's more to this story than you've explained so far. -- Craig Ringer http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
