[fix](merge-on-write) fix duplicate keys occur when be restart (#22437)

For mow table, delete bitmap of stale rowsets has not been persisted. When be restart, duplicate keys will occur if read stale rowsets.
Therefore, for the mow table, we do not allow reading the stale rowsets. Although this may result in VERSION_ALREADY_MERGED error when query after be restart, its probability of occurrence is relatively low.

be/src/olap/tablet_meta.cpp

@@ -507,17 +507,26 @@ void TabletMeta::init_from_pb(const TabletMetaPB& tablet_meta_pb) {
  // init _schema
  _schema->init_from_pb(tablet_meta_pb.schema());
 
+ if (tablet_meta_pb.has_enable_unique_key_merge_on_write()) {
+ _enable_unique_key_merge_on_write = tablet_meta_pb.enable_unique_key_merge_on_write();
+ }
+
  // init _rs_metas
  for (auto& it : tablet_meta_pb.rs_metas()) {
  RowsetMetaSharedPtr rs_meta(new RowsetMeta());
  rs_meta->init_from_pb(it);
  _rs_metas.push_back(std::move(rs_meta));
  }
 
- for (auto& it : tablet_meta_pb.stale_rs_metas()) {
- RowsetMetaSharedPtr rs_meta(new RowsetMeta());
- rs_meta->init_from_pb(it);
- _stale_rs_metas.push_back(std::move(rs_meta));
+ // For mow table, delete bitmap of stale rowsets has not been persisted.
+ // When be restart, query should not read the stale rowset, otherwise duplicate keys
+ // will be read out. Therefore, we don't add them to _stale_rs_meta for mow table.
+ if (!_enable_unique_key_merge_on_write) {
+ for (auto& it : tablet_meta_pb.stale_rs_metas()) {
+ RowsetMetaSharedPtr rs_meta(new RowsetMeta());
+ rs_meta->init_from_pb(it);
+ _stale_rs_metas.push_back(std::move(rs_meta));
+ }
  }
 
  if (tablet_meta_pb.has_in_restore_mode()) {
@@ -533,10 +542,6 @@ void TabletMeta::init_from_pb(const TabletMetaPB& tablet_meta_pb) {
  _cooldown_meta_id = tablet_meta_pb.cooldown_meta_id();
  }
 
- if (tablet_meta_pb.has_enable_unique_key_merge_on_write()) {
- _enable_unique_key_merge_on_write = tablet_meta_pb.enable_unique_key_merge_on_write();
- }
-
  if (tablet_meta_pb.has_delete_bitmap()) {
  int rst_ids_size = tablet_meta_pb.delete_bitmap().rowset_ids_size();
  int seg_ids_size = tablet_meta_pb.delete_bitmap().segment_ids_size();