Instead of "running out of disk space PANIC" we should just write to an emergency location within PGDATA
This merely buys you some time, but with aggressive and sustained write throughput you are left on the same spot. Practically speaking it's the same situation as increasing the pg_xlog disk space.
and log very loudly that the SA isn't paying attention. Perhaps if that area starts to get to an unhappy place we immediately bounce into read-only mode and log even more loudly that the SA should be fired. I would think read-only mode is safer and more polite than an PANIC crash.
I agree it is better than PANIC, but read-only mode is definitely also a form of throttling; a much more abrupt and unfriendly one if I may add.
