Fix memory leak when GC is turned off

Author: poojanilangekar

src/concurrency/timestamp_ordering_transaction_manager.cpp

@@ -775,14 +775,13 @@ ResultType TimestampOrderingTransactionManager::CommitTransaction(
     gc_object_set->emplace_back(database_oid, table_oid, index_oid);
   }
 
-  // Call the GetIterator() function to explicitly lock the cuckoohash
-  // and initilaize the iterator
-  auto rw_set_lt = rw_set.GetConstIterator();
-
   oid_t database_id = 0;
   if (static_cast<StatsType>(settings::SettingsManager::GetInt(settings::SettingId::stats_mode)) !=
       StatsType::INVALID) {
     if (!rw_set.IsEmpty()) {
+      // Call the GetIterator() function to explicitly lock the cuckoohash
+      // and initilaize the iterator
+      auto rw_set_lt = rw_set.GetConstIterator();
       const auto tile_group_id = rw_set_lt.begin()->first.block;
       database_id = manager.GetTileGroup(tile_group_id)->GetDatabaseId();
     }
@@ -793,9 +792,10 @@ ResultType TimestampOrderingTransactionManager::CommitTransaction(
   // 2. install an empty version for delete operations;
   // 3. install a new tuple for insert operations.
   // Iterate through each item pointer in the read write set
+
   // TODO: This might be inefficient since we will have to get the
   // tile_group_header for each entry. Check if this needs to be consolidated
-  for (const auto &tuple_entry : rw_set_lt) {
+  for (const auto &tuple_entry : rw_set.GetConstIterator()) {
     ItemPointer item_ptr = tuple_entry.first;
     oid_t tile_group_id = item_ptr.block;
     oid_t tuple_slot = item_ptr.offset;
@@ -951,15 +951,13 @@ ResultType TimestampOrderingTransactionManager::AbortTransaction(
     gc_object_set->emplace_back(database_oid, table_oid, index_oid);
   }
 
-
-  // Call the GetIterator() function to explicitly lock the cuckoohash
-  // and initilaize the iterator
-  auto rw_set_lt = rw_set.GetConstIterator();
-
   oid_t database_id = 0;
   if (static_cast<StatsType>(settings::SettingsManager::GetInt(settings::SettingId::stats_mode)) !=
       StatsType::INVALID) {
     if (!rw_set.IsEmpty()) {
+      // Call the GetIterator() function to explicitly lock the cuckoohash
+      // and initilaize the iterator
+      auto rw_set_lt = rw_set.GetConstIterator();
       const auto tile_group_id = rw_set_lt.begin()->first.block;
       database_id = manager.GetTileGroup(tile_group_id)->GetDatabaseId();
     }
@@ -968,7 +966,7 @@ ResultType TimestampOrderingTransactionManager::AbortTransaction(
   // Iterate through each item pointer in the read write set
   // TODO: This might be inefficient since we will have to get the
   // tile_group_header for each entry. Check if this needs to be consolidated
-  for (const auto &tuple_entry : rw_set_lt) {
+  for (const auto &tuple_entry : rw_set.GetConstIterator()) {
     ItemPointer item_ptr = tuple_entry.first;
     oid_t tile_group_id = item_ptr.block;
     oid_t tuple_slot = item_ptr.offset;