[GitHub] [incubator-doris] yangzhg commented on a change in pull request #3228: Fix output results may incorrect when using intersect and except statements

[GitBox <gi...@apache.org>]

yangzhg commented on a change in pull request #3228: Fix output results may  incorrect  when using intersect and except statements
URL: https://github.com/apache/incubator-doris/pull/3228#discussion_r400632518
 
 

 ##########
 File path: be/src/exec/except_node.cpp
 ##########
 @@ -179,17 +137,21 @@ Status ExceptNode::get_next(RuntimeState* state, RowBatch* out_batch, bool* eos)
     if (reached_limit()) {
         return Status::OK();
     }
+    int64_t tuple_buf_size;
+    uint8_t* tuple_buf;
+    RETURN_IF_ERROR(
+            out_batch->resize_and_allocate_tuple_buffer(state, &tuple_buf_size, &tuple_buf));
     uint32_t previous_hash = -1;
     TupleRow* previous_row = nullptr;
     while (_hash_tbl_iterator.has_next()) {
+        VLOG_ROW << "find row: "
+                 << get_row_output_string(_hash_tbl_iterator.get_row(), child(0)->row_desc())
+                 << " matched: " << _hash_tbl_iterator.matched();
         if (!_hash_tbl_iterator.matched()) {
             if (previous_hash != _hash_tbl_iterator.get_hash() ||
                 !equals(previous_row, _hash_tbl_iterator.get_row())) {
 
 Review comment:
   duplicated values will be iterate when get next,and deduplicate can reduce the cost of probe,you can find detail in hash_table.h,hash table in doris is not same with the common sense hashtable 

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