fix some purge bug

src/storage/compaction/ob_partition_merge_builder.cpp

@@ -124,10 +124,13 @@ int ObMacroBlockBuilder::open(storage::ObSSTableMergeCtx& ctx, const int64_t idx
                 ctx.sstable_version_range_.snapshot_version_,
                 ctx.log_ts_range_.end_log_ts_))) {
           STORAGE_LOG(WARN, "fail to init mark deletion maker, skip maker", K(ret));
+          mark_deletion_maker_->~ObBlockMarkDeletionMaker();
           mark_deletion_maker_ = NULL;
           ret = OB_SUCCESS;
+          desc_.mark_deletion_maker_ = NULL;
+        } else {
+          desc_.mark_deletion_maker_ = mark_deletion_maker_;
         }
-        desc_.mark_deletion_maker_ = mark_deletion_maker_;
       }
     } else {
       desc_.mark_deletion_maker_ = NULL;

src/storage/memtable/ob_memtable_iterator.cpp

@@ -240,7 +240,6 @@ int ObMemtableScanIterator::prepare_scan()
     TRANS_LOG(WARN, "get snapshot info failed", K(ret));
   } else if (OB_FAIL(get_real_range(cur_range_.get_range(), range))) {
     TRANS_LOG(WARN, "fail to get_real_range", K(ret), K(cur_range_));
-    ret = OB_ITER_END;
   } else if (OB_FAIL(ObMemtableKey::build(
                  start_key, param_->table_id_, *param_->out_cols_, &range.get_start_key(), *context_->allocator_))) {
     TRANS_LOG(WARN, "start key build fail", K(param_->table_id_), K(range));