NobiGo commented on code in PR #3851:
URL: https://github.com/apache/calcite/pull/3851#discussion_r1678663563


##########
core/src/main/java/org/apache/calcite/plan/volcano/VolcanoPlanner.java:
##########
@@ -982,11 +982,17 @@ void propagateCostImprovements(RelNode rel) {
         if (!relNode.getTraitSet().satisfies(subset.getTraitSet())) {
           continue;
         }
-        if (!cost.isLt(subset.bestCost)) {
+
+        // Update subset best and best's cost when we find a cheaper rel
+        if (relNode != subset.best && !cost.isLt(subset.bestCost)) {
           continue;
         }
-        // Update subset best cost when we find a cheaper rel or the current
-        // best's cost is changed
+
+        // Update the current best's cost when we find cost is changed
+        if (relNode == subset.best && cost.equals(subset.bestCost)) {

Review Comment:
   @mihaibudiu , To my knowledge, Java documentation and Java annotation are 
the same as code comments.  So maybe as you say comment is more eloquently 
here. And if we just describe the code code does, I will change the doc to :
   `The Best RelNode's cost can be  changed in propagate progress, as shown by 
the test {@link JdbcAdapterTest.testVolcanoPlannerInternalValid}`



-- 
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.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]

Reply via email to