amaliujia commented on a change in pull request #2006:
URL: https://github.com/apache/calcite/pull/2006#discussion_r439784248
##########
File path:
core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableMergeJoin.java
##########
@@ -222,6 +277,30 @@ public static boolean isMergeJoinSupported(JoinRelType
joinType) {
return mapping;
}
+ private RelCollation extendCollation(RelCollation collation, List<Integer>
keys) {
+ List<RelFieldCollation> fieldsForNewCollation = new
ArrayList<>(keys.size());
+ fieldsForNewCollation.addAll(collation.getFieldCollations());
+ Set<Integer> keySet = new HashSet<>(keys);
Review comment:
to add a bit explanation on the example above, the only usefulness of
pushed collocations on [d, c], is just to maintain increasing order when move
left pointer on left join input during merging. Thus [c, d] will achieve the
same thing.
----------------------------------------------------------------
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:
[email protected]
