Here is the full process list at the time it stopped working (I have changed the actual username, db and IP for security). Would the idle in transaction process be the culprit?
postgres 5639 0.1 24.3 3428264 2970236 ? Ss Aug14 1:54 postgres: startup process recovering 000000010000053D0000003F waiting
postgres 5642 0.0 21.4 3428356 2613252 ? Ss Aug14 0:30 postgres: writer process
postgres 5659 0.0 0.0 177524 788 ? Ss Aug14 0:03 postgres: stats collector process
postgres 7159 1.2 0.1 3451360 18352 ? Ss Aug14 17:31 postgres: wal receiver process streaming 549/216B3730
postgres 10403 0.0 0.2 3430372 25920 ? Ss Aug14 0:31 postgres: user db x.x.x.x(61656) idle in transaction
postgres 19933 0.0 0.4 3426604 49564 ? S Aug05 0:06 /usr/pgsql-9.1/bin/postmaster -p 5432 -D /var/lib/pgsql/9.1/data
postgres 19935 0.0 0.0 175288 396 ? Ss Aug05 0:13 postgres: logger process
postgres 21133 0.0 0.2 3443600 30680 ? Ss 09:28 0:00 postgres: user db x.x.x.x(64430) idle
postgres 21134 0.4 0.2 3430160 27656 ? Ss 09:28 0:16 postgres: user db x.x.x.x(64431) idle
root 21529 0.0 0.0 103240 844 pts/0 S+ 10:33 0:00 grep --color postgres
Thanks,
Andrew