[GitHub] [incubator-doris] morningman commented on a change in pull request #3886: [Planner] Set MysqlScanNode's cardinality to avoid unexpected shuffle join

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

morningman commented on a change in pull request #3886:
URL: https://github.com/apache/incubator-doris/pull/3886#discussion_r440610898



##########
File path: fe/src/main/java/org/apache/doris/planner/DistributedPlanner.java
##########
@@ -294,6 +294,11 @@ private PlanFragment createHashJoinFragment(HashJoinNode node, PlanFragment righ
         // broadcast: send the rightChildFragment's output to each node executing
         // the leftChildFragment; the cost across all nodes is proportional to the
         // total amount of data sent
+
+        // NOTICE(cmy): for now, only MysqlScanNode and OlapScanNode has Cardinality. And MysqlScanNode's Cardinality
+        // is always 0. Other ScanNode's cardinality is -1, so they won't be able the calculate the cost of

Review comment:
       done




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org



---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@doris.apache.org
For additional commands, e-mail: commits-help@doris.apache.org