From be7b835c5c81acd401f5161b0d9cd1dcffa9148d Mon Sep 17 00:00:00 2001
From: amyangfei <amyangfei@gmail.com>
Date: Thu, 22 Oct 2020 20:04:07 +0800
Subject: [PATCH] cherry pick #1017 to release-4.0

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>
---
 cdc/processor.go | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/cdc/processor.go b/cdc/processor.go
index 10d813f8f0c..dd125b768a7 100644
--- a/cdc/processor.go
+++ b/cdc/processor.go
@@ -551,8 +551,11 @@ func (p *processor) flushTaskStatusAndPosition(ctx context.Context) error {
 	for _, tableID := range tablesToRemove {
 		p.removeTable(tableID)
 	}
-	p.statusModRevision = newModRevision
-	p.status = newTaskStatus
+	// newModRevision == 0 means status is not updated
+	if newModRevision > 0 {
+		p.statusModRevision = newModRevision
+		p.status = newTaskStatus
+	}
 	syncTableNumGauge.
 		WithLabelValues(p.changefeedID, p.captureInfo.AdvertiseAddr).
 		Set(float64(len(p.status.Tables)))