3 files changed, 26 insertions, 15 deletions
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 3c9ebbcd69c..a9343b7b59e 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -103,11 +103,10 @@ pgstat_fetch_stat_backend_by_pid(int pid, BackendType *bktype)
 	if (bktype)
 		*bktype = B_INVALID;
 
-	/*
-	 * This could be an auxiliary process but these do not report backend
-	 * statistics due to pgstat_tracks_backend_bktype(), so there is no need
-	 * for an extra call to AuxiliaryPidGetProc().
-	 */
+	/* this could be an auxiliary process */
+	if (!proc)
+		proc = AuxiliaryPidGetProc(pid);
+
 	if (!proc)
 		return NULL;
 
@@ -117,6 +116,10 @@ pgstat_fetch_stat_backend_by_pid(int pid, BackendType *bktype)
 	if (!beentry)
 		return NULL;
 
+	/* check if the backend type tracks statistics */
+	if (!pgstat_tracks_backend_bktype(beentry->st_backendType))
+		return NULL;
+
 	backend_stats = pgstat_fetch_stat_backend(procNumber);
 	if (!backend_stats)
 		return NULL;
@@ -125,10 +128,6 @@ pgstat_fetch_stat_backend_by_pid(int pid, BackendType *bktype)
 	if (beentry->st_procpid != pid)
 		return NULL;
 
-	/* backend may be gone, so recheck in case */
-	if (beentry->st_backendType == B_INVALID)
-		return NULL;
-
 	if (bktype)
 		*bktype = beentry->st_backendType;
 
diff --git a/src/backend/utils/activity/pgstat_wal.c b/src/backend/utils/activity/pgstat_wal.c
index 943be0cbeef..5d3da4b674e 100644
--- a/src/backend/utils/activity/pgstat_wal.c
+++ b/src/backend/utils/activity/pgstat_wal.c
@@ -55,6 +55,7 @@ pgstat_report_wal(bool force)
 
 	/* flush IO stats */
 	pgstat_flush_io(nowait);
+	(void) pgstat_flush_backend(nowait, PGSTAT_BACKEND_FLUSH_IO);
 }
 
 /*
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 68830db8633..0212d8d5906 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1919,19 +1919,30 @@ Datum
 pg_stat_reset_backend_stats(PG_FUNCTION_ARGS)
 {
 	PGPROC	   *proc;
+	PgBackendStatus *beentry;
+	ProcNumber	procNumber;
 	int			backend_pid = PG_GETARG_INT32(0);
 
 	proc = BackendPidGetProc(backend_pid);
 
-	/*
-	 * This could be an auxiliary process but these do not report backend
-	 * statistics due to pgstat_tracks_backend_bktype(), so there is no need
-	 * for an extra call to AuxiliaryPidGetProc().
-	 */
+	/* This could be an auxiliary process */
+	if (!proc)
+		proc = AuxiliaryPidGetProc(backend_pid);
+
 	if (!proc)
 		PG_RETURN_VOID();
 
-	pgstat_reset(PGSTAT_KIND_BACKEND, InvalidOid, GetNumberFromPGProc(proc));
+	procNumber = GetNumberFromPGProc(proc);
+
+	beentry = pgstat_get_beentry_by_proc_number(procNumber);
+	if (!beentry)
+		PG_RETURN_VOID();
+
+	/* Check if the backend type tracks statistics */
+	if (!pgstat_tracks_backend_bktype(beentry->st_backendType))
+		PG_RETURN_VOID();
+
+	pgstat_reset(PGSTAT_KIND_BACKEND, InvalidOid, procNumber);
 
 	PG_RETURN_VOID();
 }