Lower error level from PANIC to FATAL when restoring slots at startup

michaelpq · michaelpq · commit 6286efb5240f · 2018-11-02T07:59:24.000+09:00
When restoring slot information from disk at startup and filling in shared memory information, the startup process would issue a PANIC message if more slots are found than what max_replication_slots allows, and then Postgres generates a core dump, recommending to increase max_replication_slots. This gives users a switch to crash Postgres at will by creating slots, lower the configuration to not support it, and then restart it. Making Postgres crash hard in this case is overdoing it just to give a recommendation to users. So instead use a FATAL, which makes Postgres fail to start without crashing, still giving the recommendation. This is more consistent with what happens for prepared transactions for example. Author: Michael Paquier Reviewed-by: Andres Freund Discussion: https://postgr.es/m/20181030025109.GD1644@paquier.xyz
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
@@ -1563,7 +1563,7 @@ RestoreSlotFromDisk(const char *name)
 	}
 
 	if (!restored)
-		ereport(PANIC,
+		ereport(FATAL,
 				(errmsg("too many replication slots active before shutdown"),
 				 errhint("Increase max_replication_slots and try again.")));
 }

Original file line number	Diff line number	Diff line change
`@@ -1563,7 +1563,7 @@ RestoreSlotFromDisk(const char *name)`
`1563`	`1563`	`}`
`1564`	`1564`
`1565`	`1565`	`if (!restored)`
`1566`		`- ereport(PANIC,`
	`1566`	`+ ereport(FATAL,`
`1567`	`1567`	`(errmsg("too many replication slots active before shutdown"),`
`1568`	`1568`	`errhint("Increase max_replication_slots and try again.")));`
`1569`	`1569`	`}`