Add history reset

Author: Medvecrab

collector.c

@@ -961,6 +961,12 @@ pgws_collector_main(Datum main_arg)
 				}
 				shm_mq_detach(mqh);
 			}
+			else if (request == HISTORY_RESET)
+			{
+				/* Reset history */
+				pfree(observations.items);
+				alloc_history(&observations, pgws_historySize);
+			}
 			else if (request == PROFILE_RESET)
 			{
 				/* Reset profile hash */

pg_wait_sampling--1.1--1.2.sql

@@ -102,6 +102,14 @@ CREATE VIEW pg_wait_sampling_profile_extended AS
 
 GRANT SELECT ON pg_wait_sampling_profile_extended TO PUBLIC;
 
+CREATE FUNCTION pg_wait_sampling_reset_history()
+RETURNS void
+AS 'MODULE_PATHNAME'
+LANGUAGE C VOLATILE STRICT;
+
+-- Don't want this to be available to non-superusers.
+REVOKE ALL ON FUNCTION pg_wait_sampling_reset_history() FROM PUBLIC;
+
 --CREATE VIEW pg_wait_sampling_profile AS
 --	SELECT pid, event_type, event, queryid, SUM(count) FROM pg_wait_sampling_profile_extended
 --	GROUP BY pid, event_type, event, queryid;

pg_wait_sampling.c

@@ -1439,6 +1439,34 @@ pg_wait_sampling_reset_profile(PG_FUNCTION_ARGS)
 	PG_RETURN_VOID();
 }
 
+PG_FUNCTION_INFO_V1(pg_wait_sampling_reset_history);
+Datum
+pg_wait_sampling_reset_history(PG_FUNCTION_ARGS)
+{
+	LOCKTAG		collectorTag;
+
+	check_shmem();
+
+	pgws_init_lock_tag(&queueTag, PGWS_QUEUE_LOCK);
+
+	LockAcquire(&queueTag, ExclusiveLock, false, false);
+
+	pgws_init_lock_tag(&collectorTag, PGWS_COLLECTOR_LOCK);
+	LockAcquire(&collectorTag, ExclusiveLock, false, false);
+	pgws_collector_hdr->request = HISTORY_RESET;
+	LockRelease(&collectorTag, ExclusiveLock, false);
+	
+	if (!pgws_collector_hdr->latch)
+		ereport(ERROR, (errcode(ERRCODE_INTERNAL_ERROR),
+						errmsg("pg_wait_sampling collector wasn't started")));
+
+	SetLatch(pgws_collector_hdr->latch);
+
+	LockRelease(&queueTag, ExclusiveLock, false);
+
+	PG_RETURN_VOID();
+}
+
 //TODO OBSOLETE
 PG_FUNCTION_INFO_V1(pg_wait_sampling_get_history);
 Datum

pg_wait_sampling.h

@@ -100,6 +100,7 @@ typedef enum
 {
 	NO_REQUEST,
 	HISTORY_REQUEST,
+	HISTORY_RESET,
 	PROFILE_REQUEST,
 	PROFILE_RESET
 } SHMRequest;