From 2901293d8b8996b349da4b85daeb1d884e260600 Mon Sep 17 00:00:00 2001
From: maxiang <maxiang9527@126.com>
Date: Sat, 29 May 2021 10:12:08 +0800
Subject: [PATCH] update
 src/gausskernel/storage/replication/logical/logical.cpp.

---
 src/gausskernel/storage/replication/logical/logical.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/gausskernel/storage/replication/logical/logical.cpp b/src/gausskernel/storage/replication/logical/logical.cpp
index 127c6e69d..3924db918 100644
--- a/src/gausskernel/storage/replication/logical/logical.cpp
+++ b/src/gausskernel/storage/replication/logical/logical.cpp
@@ -825,6 +825,14 @@ void LogicalIncreaseRestartDecodingForSlot(XLogRecPtr current_lsn, XLogRecPtr re
  */
 void LogicalConfirmReceivedLocation(XLogRecPtr lsn)
 {
+    /*
+     * Check if the slot is not moving backwards. Logical slots have confirmed
+     * consumption up to confirmed_lsn, meaning that data older than that is
+     * not available anymore.
+     */
+    if (XLByteLE(lsn, t_thrd.slot_cxt.MyReplicationSlot->data.confirmed_flush))
+        return;
+
     Assert(!XLByteEQ(lsn, InvalidXLogRecPtr));
     (void)LWLockAcquire(LogicalReplicationSlotPersistentDataLock, LW_EXCLUSIVE);
     /* Do an unlocked check for candidate_lsn first. */