From: David Steele [mailto:da...@pgmasters.net] > > Can't we use SIGKILL instead of SIGINT/SIGTERM to stop the grandchildren, > just in case they are slow to respond to or ignore SIGINT/SIGTERM? That > matches the idea of pg_ctl's immediate shutdown. > > -1, at least not immediately. Archivers can be complex processes and > they should be given the chance to do a graceful shutdown.
I agree that the user's archiver program should receive the chance for graceful stop in smart or fast shutdown. But I think in immediate shutdown, all should stop immediately. That's what I expect from the word "immediate." If the grandchildren left running don't disturb the cleanup of PostgreSQL's resources (shared memory, file/directory access, etc.) or restart of PostgreSQL, we may well be able to just advice the grandchildren to stop immediately with SIGINT/SIGTERM. However, for example, in the failover of shared-disk HA clustering, when the clustering software stops PostgreSQL with "pg_ctl stop -m immediate" and then tries to unmount the file systems for $PGDATA and archived WAL, the unmount may take time or fail due to the access from PostgreSQL's grandchildren. Regards Takayuki Tsunakawa
