diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index cc0d9a05d9f..fb4c860bdea 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -2191,6 +2191,8 @@ XLogWrite(XLogwrtRqst WriteRqst, TimeLineID tli, bool flexible)
 				/* Measure I/O timing to write WAL data */
 				if (track_wal_io_timing)
 					INSTR_TIME_SET_CURRENT(start);
+				else
+					INSTR_TIME_SET_ZERO(start);
 
 				pgstat_report_wait_start(WAIT_EVENT_WAL_WRITE);
 				written = pg_pwrite(openLogFile, from, nleft, startoffset);
@@ -8151,6 +8153,8 @@ issue_xlog_fsync(int fd, XLogSegNo segno, TimeLineID tli)
 	/* Measure I/O timing to sync the WAL file */
 	if (track_wal_io_timing)
 		INSTR_TIME_SET_CURRENT(start);
+	else
+		INSTR_TIME_SET_ZERO(start);
 
 	pgstat_report_wait_start(WAIT_EVENT_WAL_SYNC);
 	switch (sync_method)
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 8075828e8a6..800a4248c95 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -1017,6 +1017,8 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 			if (track_io_timing)
 				INSTR_TIME_SET_CURRENT(io_start);
+			else
+				INSTR_TIME_SET_ZERO(io_start);
 
 			smgrread(smgr, forkNum, blockNum, (char *) bufBlock);
 
@@ -2902,6 +2904,8 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 
 	if (track_io_timing)
 		INSTR_TIME_SET_CURRENT(io_start);
+	else
+		INSTR_TIME_SET_ZERO(io_start);
 
 	/*
 	 * bufToWrite is either the shared buffer or a copy, as appropriate.
diff --git a/src/backend/storage/file/buffile.c b/src/backend/storage/file/buffile.c
index c5464b6aa62..0a51624df3b 100644
--- a/src/backend/storage/file/buffile.c
+++ b/src/backend/storage/file/buffile.c
@@ -446,6 +446,8 @@ BufFileLoadBuffer(BufFile *file)
 
 	if (track_io_timing)
 		INSTR_TIME_SET_CURRENT(io_start);
+	else
+		INSTR_TIME_SET_ZERO(io_start);
 
 	/*
 	 * Read whatever we can get, up to a full bufferload.
@@ -525,6 +527,8 @@ BufFileDumpBuffer(BufFile *file)
 
 		if (track_io_timing)
 			INSTR_TIME_SET_CURRENT(io_start);
+		else
+			INSTR_TIME_SET_ZERO(io_start);
 
 		bytestowrite = FileWrite(thisfile,
 								 file->buffer.data + wpos,
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index d79d71a8515..f4123e7de7e 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -1401,6 +1401,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 		Assert(timeout >= 0 && timeout <= INT_MAX);
 		cur_timeout = timeout;
 	}
+	else
+		INSTR_TIME_SET_ZERO(start_time);
 
 	pgstat_report_wait_start(wait_event_info);
 
diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c
index 00627830c47..f907f5d4e8d 100644
--- a/src/bin/psql/common.c
+++ b/src/bin/psql/common.c
@@ -1276,6 +1276,8 @@ DescribeQuery(const char *query, double *elapsed_msec)
 
 	if (timing)
 		INSTR_TIME_SET_CURRENT(before);
+	else
+		INSTR_TIME_SET_ZERO(before);
 
 	/*
 	 * To parse the query but not execute it, we prepare it, using the unnamed
@@ -1406,6 +1408,8 @@ ExecQueryAndProcessResults(const char *query,
 
 	if (timing)
 		INSTR_TIME_SET_CURRENT(before);
+	else
+		INSTR_TIME_SET_ZERO(before);
 
 	if (pset.bind_flag)
 		success = PQsendQueryParams(pset.db, query, pset.bind_nparams, NULL, (const char * const *) pset.bind_params, NULL, NULL, 0);
@@ -1702,6 +1706,8 @@ ExecQueryUsingCursor(const char *query, double *elapsed_msec)
 
 	if (timing)
 		INSTR_TIME_SET_CURRENT(before);
+	else
+		INSTR_TIME_SET_ZERO(before);
 
 	/* if we're not in a transaction, start one */
 	if (PQtransactionStatus(pset.db) == PQTRANS_IDLE)