[GitHub] [incubator-doris] yangzhg commented on a change in pull request #3148: improve performent of hash join in some case

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

yangzhg commented on a change in pull request #3148: improve performent of hash join in some case
URL: https://github.com/apache/incubator-doris/pull/3148#discussion_r395410965
 
 

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 File path: be/src/exec/hash_join_node_ir.cpp
 ##########
 @@ -137,11 +137,20 @@ int HashJoinNode::process_probe_batch(RowBatch* out_batch, RowBatch* probe_batch
     return rows_returned;
 }
 
+// when build table has too many duplicated rows, the collisions will be very serious,
+// so in some case will don't need to store duplicated value in hash table, we can build an unique one
 void HashJoinNode::process_build_batch(RowBatch* build_batch) {
     // insert build row into our hash table
     for (int i = 0; i < build_batch->num_rows(); ++i) {
-        _hash_tbl->insert(build_batch->get_row(i));
+        if (_join_op == TJoinOp::LEFT_ANTI_JOIN|| _join_op == TJoinOp::RIGHT_ANTI_JOIN
 
 Review comment:
   done

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