[refer #PGPRO-6601]: Removed "init_lock_tag" function which interferes with

the same named function in the AQO extension.
Init the "receiver" shared memory queue more carefully using an "ExclusiveLock"
lock.

Tags: pg_wait_sampling.

Author: rzharkov

collector.c

@@ -445,12 +445,9 @@ collector_main(Datum main_arg)
 		/* Handle request if any */
 		if (collector_hdr->request != NO_REQUEST)
 		{
-			LOCKTAG		tag;
 			SHMRequest	request;
 
-			init_lock_tag(&tag, PGWS_COLLECTOR_LOCK);
-
-			LockAcquire(&tag, ExclusiveLock, false, false);
+			LockAcquire(&collectorTag, ExclusiveLock, false, false);
 			request = collector_hdr->request;
 			collector_hdr->request = NO_REQUEST;
 
@@ -494,7 +491,7 @@ collector_main(Datum main_arg)
 				hash_destroy(profile_hash);
 				profile_hash = make_profile_hash();
 			}
-			LockRelease(&tag, ExclusiveLock, false);
+			LockRelease(&collectorTag, ExclusiveLock, false);
 		}
 	}
 

pg_wait_sampling.c

@@ -56,7 +56,24 @@ CollectorShmqHeader	   *collector_hdr = NULL;
 /* Receiver (backend) local shm_mq pointers and lock */
 shm_mq		   *recv_mq = NULL;
 shm_mq_handle  *recv_mqh = NULL;
-LOCKTAG			queueTag;
+
+const LOCKTAG	queueTag = {
+	.locktag_field1 = PG_WAIT_SAMPLING_MAGIC,
+	.locktag_field2 = PGWS_QUEUE_LOCK,
+	.locktag_field3 = 0,
+	.locktag_field4 = 0,
+	.locktag_type = LOCKTAG_USERLOCK,
+	.locktag_lockmethodid = USER_LOCKMETHOD
+};
+
+const LOCKTAG	collectorTag = {
+	.locktag_field1 = PG_WAIT_SAMPLING_MAGIC,
+	.locktag_field2 = PGWS_COLLECTOR_LOCK,
+	.locktag_field3 = 0,
+	.locktag_field4 = 0,
+	.locktag_type = LOCKTAG_USERLOCK,
+	.locktag_lockmethodid = USER_LOCKMETHOD
+};
 
 #if PG_VERSION_NUM >= 150000
 static shmem_request_hook_type prev_shmem_request_hook = NULL;
@@ -563,21 +580,9 @@ typedef struct
 	ProfileItem	   *items;
 } Profile;
 
-void
-init_lock_tag(LOCKTAG *tag, uint32 lock)
-{
-	tag->locktag_field1 = PG_WAIT_SAMPLING_MAGIC;
-	tag->locktag_field2 = lock;
-	tag->locktag_field3 = 0;
-	tag->locktag_field4 = 0;
-	tag->locktag_type = LOCKTAG_USERLOCK;
-	tag->locktag_lockmethodid = USER_LOCKMETHOD;
-}
-
 static void *
 receive_array(SHMRequest request, Size item_size, Size *count)
 {
-	LOCKTAG			collectorTag;
 	shm_mq_result	res;
 	Size			len,
 					i;
@@ -587,13 +592,10 @@ receive_array(SHMRequest request, Size item_size, Size *count)
 	MemoryContext	oldctx;
 
 	/* Ensure nobody else trying to send request to queue */
-	init_lock_tag(&queueTag, PGWS_QUEUE_LOCK);
 	LockAcquire(&queueTag, ExclusiveLock, false, false);
 
-	recv_mq = shm_mq_create(collector_mq, COLLECTOR_QUEUE_SIZE);
-
-	init_lock_tag(&collectorTag, PGWS_COLLECTOR_LOCK);
 	LockAcquire(&collectorTag, ExclusiveLock, false, false);
+	recv_mq = shm_mq_create(collector_mq, COLLECTOR_QUEUE_SIZE);
 	collector_hdr->request = request;
 	LockRelease(&collectorTag, ExclusiveLock, false);
 
@@ -754,23 +756,17 @@ PG_FUNCTION_INFO_V1(pg_wait_sampling_reset_profile);
 Datum
 pg_wait_sampling_reset_profile(PG_FUNCTION_ARGS)
 {
-	LOCKTAG		tag;
-	LOCKTAG		collectorTag;
-
 	check_shmem();
 
-	init_lock_tag(&tag, PGWS_QUEUE_LOCK);
-
-	LockAcquire(&tag, ExclusiveLock, false, false);
+	LockAcquire(&queueTag, ExclusiveLock, false, false);
 
-	init_lock_tag(&collectorTag, PGWS_COLLECTOR_LOCK);
 	LockAcquire(&collectorTag, ExclusiveLock, false, false);
 	collector_hdr->request = PROFILE_RESET;
 	LockRelease(&collectorTag, ExclusiveLock, false);
 
 	SetLatch(collector_hdr->latch);
 
-	LockRelease(&tag, ExclusiveLock, false);
+	LockRelease(&queueTag, ExclusiveLock, false);
 
 	PG_RETURN_VOID();
 }

pg_wait_sampling.h

@@ -70,12 +70,14 @@ typedef struct
 	bool			profileQueries;
 } CollectorShmqHeader;
 
+extern const LOCKTAG	queueTag;
+extern const LOCKTAG	collectorTag;
+
 /* pg_wait_sampling.c */
 extern void check_shmem(void);
 extern CollectorShmqHeader *collector_hdr;
 extern shm_mq			   *collector_mq;
 extern uint64			   *proc_queryids;
-extern void init_lock_tag(LOCKTAG *tag, uint32 lock);
 
 /* collector.c */
 extern void register_wait_collector(void);