From 31dd24f902d081e50f16a19d5fb3d7b0fdfae5b5 Mon Sep 17 00:00:00 2001
From: lidezhu <47731263+lidezhu@users.noreply.github.com>
Date: Fri, 1 Mar 2024 17:14:01 +0800
Subject: [PATCH] barrier(ticdc): fix wrong barrier ts under frequent ddl
 scenario (#10669)

close pingcap/tiflow#10668
---
 cdc/owner/ddl_manager.go | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/cdc/owner/ddl_manager.go b/cdc/owner/ddl_manager.go
index a603469436c..c2cecc367b4 100644
--- a/cdc/owner/ddl_manager.go
+++ b/cdc/owner/ddl_manager.go
@@ -456,7 +456,20 @@ func (m *ddlManager) barrier() *schedulepb.BarrierWithMinTs {
 			// barrier related physical tables
 			ids := getRelatedPhysicalTableIDs(ddl)
 			for _, id := range ids {
-				tableBarrierMap[id] = ddl.CommitTs
+				// The same physical table may have multiple related ddl events when calculating barrier.
+				// Example cases:
+				// 1. The logical id of the same partition table may change after change partition.
+				//	So the related ddls may be considered for different tables.
+				//  And they may be returned by `getAllTableNextDDL` at the same time.
+				// 2. The result of `getAllTableNextDDL` may influence the same physical tables as `ddlManager.justSentDDL`.
+				// So we always choose the min commitTs of all ddls related to the same physical table as the barrierTs.
+				if ts, ok := tableBarrierMap[id]; ok {
+					if ddl.CommitTs < ts {
+						tableBarrierMap[id] = ddl.CommitTs
+					}
+				} else {
+					tableBarrierMap[id] = ddl.CommitTs
+				}
 			}
 		}
 	}