Michael Paesold escribió: > Simon Riggs wrote: > Hmm, I am not sure we are there, yet. Autovacuum does take extra care to > vacuum tables nearing xid wrap-around, right? It even does so when > autovacuum is disabled in the configuration. > > So in case a vacuum is needed for that very reason, the vacuum should *not* > be canceled, of course. So we don't really need the information, whether > the AV worker is doing VACUUM or ANALYZE, but whether it is critical > against xid wrap-around. Could that be done as easily as in Alvaro's patch > for distinguishing vacuum/analyze? Alvaro?
Yes, I think it is easy to mark the "is for xid wraparound" bit in the WorkerInfo struct and have the cancel work only if it's off. However, what I think should happen is that the signal handler for SIGINT in a worker for xid wraparound should not cancel the current vacuum. Instead turn it into a no-op, if possible. That way we also disallow a user from cancelling vacuums for xid wraparound. I think he can do that with pg_cancel_backend, and it could be dangerous. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
