Re: Too many clients - Error

John McKown <jmckown(at)prodigy(dot)net> writes:
> PostgreSQL as normally distributed only allows 32 concurrent users. You
> have exceeded this number of users. You can fix this in one of two ways.
> The hard way is to reconfigure & recompile PostgreSQL using the
> --with-maxbackends=1024 (maximum number of users is 1024!). The simple way
> is to edit the PostgreSQL startup script to include the parameter
> "-N 1024" to set the maximum number of concurrent connections to 1024.

Note you will also need to increase -B (to at least twice -N).

It may be a bad idea to raise the limit as far as 1024, unless your
platform is really configured to support that many active backends
(which means LOTS of RAM and swap space, lots of kernel open-file-table
entries, etc). The reason the default is 32 is that that roughly
corresponds to the factory-stock limits in many Unixen about size of
shared memory blocks and so forth. Don't be surprised if you have to
rejigger kernel parameter settings before you can go up very far.

> I don't see any command to list who is currently using PostgreSQL.

"ps -aux | grep postgres" (adapt to local situation...)

regards, tom lane