Merlin Moncure <mmoncure@gmail.com> writes: > On Mon, Jul 8, 2013 at 4:56 AM, Jov <amutu@amutu.com> wrote: >> my first post already try the pg_terminate_backend but failed: >> pg_terminate_backend return t but the backend still there.
> possibly a kernel problem?
The backend will keep trying to send data until the kernel informs it the connection is lost. (Anything else would be a bad idea.) So the real question here is why it's taking so long for the TCP stack to decide that the client is gone. I'm wondering what exactly you did to kill the psql session. Most ordinary ways of killing a process should result in closure of whatever connections it had open.
If you'd lost network connectivity to the client, a TCP timeout on the order of an hour wouldn't be surprising. (If you feel this is too long, you can fool with the TCP keepalive parameters.) But it seems unlikely that that's what's happening here.