> Was there idle-in-transaction in the master when the problem happened?
Shouldn't have been, but that's what I was wondering, too. I didn't check. Not sure I know how to check.
That was my guess and I mostly wanted to confirm that that could happen. Does seem like an edge case. I don't expect uncommitted transactions to be hanging around in general, or even long periods between some kind of write.
Thanks for the help.