Provide much better wait information in pg_stat_activity.

When a process is waiting for a heavyweight lock, we will now indicate
the type of heavyweight lock for which it is waiting.  Also, you can
now see when a process is waiting for a lightweight lock - in which
case we will indicate the individual lock name or the tranche, as
appropriate - or for a buffer pin.

Amit Kapila, Ildus Kurbangaliev, reviewed by me.  Lots of helpful
discussion and suggestions by many others, including Alexander
Korotkov, Vladimir Borodin, and many others.

1 files changed, 9 insertions, 4 deletions

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index b491735d2e2..ab8758661db 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -2447,13 +2447,14 @@ AbortTransaction(void)
 	 */
 	LWLockReleaseAll();
 
+	/* Clear wait information and command progress indicator */
+	pgstat_report_wait_end();
+	pgstat_progress_end_command();
+
 	/* Clean up buffer I/O and buffer context locks, too */
 	AbortBufferIO();
 	UnlockBuffers();
 
-	/* Clear command progress indicator */
-	pgstat_progress_end_command();
-
 	/* Reset WAL record construction state */
 	XLogResetInsertion();
 
@@ -4541,9 +4542,10 @@ AbortSubTransaction(void)
 	 */
 	LWLockReleaseAll();
 
+	pgstat_report_wait_end();
+	pgstat_progress_end_command();
 	AbortBufferIO();
 	UnlockBuffers();
-	pgstat_progress_end_command();
 
 	/* Reset WAL record construction state */
 	XLogResetInsertion();
@@ -4653,6 +4655,9 @@ AbortSubTransaction(void)
 	 */
 	XactReadOnly = s->prevXactReadOnly;
 
+	/* Report wait end here, when there is no further possibility of wait */
+	pgstat_report_wait_end();
+
 	RESUME_INTERRUPTS();
 }