I've got replication setup (streaming replication) between two 9.2.2 clusters. Everything went just fine on that, and it's working as expected.
Now, obviously, I'll know if my primary goes down. I just monitor him as usual.
How do I tell whether the standby has gone out of sync for whatever reason?
Obviously, I can monitor this:
ps -elf | grep "wal receiver"
but is there a situation in which the wal receiver is running, but the replication is not working, or there are errors? I know about the replay/receive xlog locations, but those can be off due to lag, of course.
What I want to know is whether there's a situation in which my standby is running, the receiver process is running, but "something" is wrong.
Sorry this isn't more definite. I'm not quite sure what I'm looking for.
Thanks,
Scott