From fb6e80f1f6866e98f9f467788eae6ee08e2da56f Mon Sep 17 00:00:00 2001
From: Tyshawn <tuyunshan@gmail.com>
Date: Sat, 12 Oct 2024 03:55:30 +0000
Subject: [PATCH] [BUG.FIX] fix duplicated memtable in tablet memtable array

---
 src/storage/ob_i_table.h                   | 4 ++--
 src/storage/tablet/ob_table_store_util.cpp | 7 +++++--
 src/storage/tablet/ob_tablet.cpp           | 5 ++++-
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/storage/ob_i_table.h b/src/storage/ob_i_table.h
index 8a87f6ceb..c1999c0a9 100644
--- a/src/storage/ob_i_table.h
+++ b/src/storage/ob_i_table.h
@@ -163,8 +163,8 @@ public:
     OB_INLINE bool is_true_major_sstable() const { return is_row_store_major_sstable() || is_column_store_major_sstable(); }
 
     OB_INLINE const common::ObTabletID &get_tablet_id() const { return tablet_id_; }
-    share::SCN get_start_scn() const { return scn_range_.start_scn_; }
-    share::SCN get_end_scn() const { return scn_range_.end_scn_; }
+    share::SCN get_start_scn() const { return scn_range_.start_scn_.atomic_get(); }
+    share::SCN get_end_scn() const { return scn_range_.end_scn_.atomic_get(); }
     OB_INLINE int64_t get_snapshot_version() const
     {
       return version_range_.snapshot_version_;
diff --git a/src/storage/tablet/ob_table_store_util.cpp b/src/storage/tablet/ob_table_store_util.cpp
index dda4d82d1..970bd4611 100644
--- a/src/storage/tablet/ob_table_store_util.cpp
+++ b/src/storage/tablet/ob_table_store_util.cpp
@@ -1072,7 +1072,10 @@ bool ObMemtableArray::exist_memtable_with_end_scn(const ObITable *table, const S
   // we need to make sure duplicate memtable was not added to tablet,
   // and ensure active memtable could be added to tablet
   bool is_exist = false;
-  if (table->get_end_scn() == end_scn && count_ >= 1) {
+  if (0 >= count_) {
+  } else if (table->get_end_scn() == end_scn || end_scn.is_max()) {
+    // Pay Attention!!!
+    // The end scn of memtable can only be max or a certain value.
     for (int64_t i = count_ - 1; i >= 0 ; --i) {
       const ObITable *memtable = memtable_array_[i];
       if (memtable == table) {
@@ -1439,4 +1442,4 @@ int ObTableStoreUtil::check_has_backup_macro_block(const ObITable *table, bool &
     }
   }
   return ret;
-}
\ No newline at end of file
+}
diff --git a/src/storage/tablet/ob_tablet.cpp b/src/storage/tablet/ob_tablet.cpp
index cdce08851..be0ea28ec 100644
--- a/src/storage/tablet/ob_tablet.cpp
+++ b/src/storage/tablet/ob_tablet.cpp
@@ -7498,7 +7498,10 @@ bool ObTablet::exist_memtable_with_end_scn(const ObITable *table, const SCN &end
   // we need to make sure duplicate memtable was not added to tablet,
   // and ensure active memtable could be added to tablet
   bool is_exist = false;
-  if (table->get_end_scn() == end_scn && memtable_count_ >= 1) {
+  if (0 >= memtable_count_) {
+  } else if (table->get_end_scn() == end_scn || end_scn.is_max()) {
+    // Pay Attention!!!
+    // The end scn of memtable can only be max or a certain value.
     for (int64_t i = memtable_count_ - 1; i >= 0 ; --i) {
       const ObIMemtable *memtable = memtables_[i];
       if (memtable == table) {