Don't auto-restart per-database autoprewarm workers.

robertmhaas · robertmhaas · commit 1459e84cb2e5 · 2019-03-18T15:22:42.000-04:00
We should try to prewarm each database only once. Otherwise, if prewarming fails for some reason, it will just keep retrying in an infnite loop. This can happen if, for example, the database has been dropped. The existing code was intended to implement the try-once behavior, but failed to do so because it neglected to set worker.bgw_restart_time to BGW_NEVER_RESTART. Mithun Cy, per a report from Hans Buschmann Discussion: http://postgr.es/m/CA+hUKGKpQJCWcgyy3QTC9vdn6uKAR_8r__A-MMm2GYfj45caag@mail.gmail.com
diff --git a/contrib/pg_prewarm/autoprewarm.c b/contrib/pg_prewarm/autoprewarm.c
@@ -840,6 +840,7 @@ apw_start_database_worker(void)
 	worker.bgw_flags =
 		BGWORKER_SHMEM_ACCESS | BGWORKER_BACKEND_DATABASE_CONNECTION;
 	worker.bgw_start_time = BgWorkerStart_ConsistentState;
+	worker.bgw_restart_time = BGW_NEVER_RESTART;
 	strcpy(worker.bgw_library_name, "pg_prewarm");
 	strcpy(worker.bgw_function_name, "autoprewarm_database_main");
 	strcpy(worker.bgw_name, "autoprewarm worker");
