rubenada commented on code in PR #3311:
URL: https://github.com/apache/calcite/pull/3311#discussion_r1315141021
##########
linq4j/src/main/java/org/apache/calcite/linq4j/EnumerableDefaults.java:
##########
@@ -4495,6 +4492,27 @@ private boolean advanceRight(TInner right, TKey
rightKey) {
}
}
+ public static int compareNullsLastForMergeJoin(@Nullable Comparable v0,
@Nullable Comparable v1) {
+ return compareNullsLastForMergeJoin(v0, v1, null);
+ }
+
+ public static int compareNullsLastForMergeJoin(@Nullable Comparable v0,
@Nullable Comparable v1,
+ @Nullable Comparator comparator) {
+ // Special code for mergeJoin algorithm: in case of two null values, they
must not be
+ // considered as equal (otherwise the join would return incorrect
results); instead, consider
+ // the first (left) value as "bigger", to advance on the right value and
continue with the
+ // algorithm
+ if (v0 == null && v1 == null) {
+ return 1;
Review Comment:
@libenchao I have committed a new approach that should handle this issue:
- Use a (control flow) BothValuesAreNullException in the Comparator to avoid
breaking its semantics
- Use an EqualityComparer (i.e. nulls are considered equal) to compare keys
from the same side
wdyt?
UPDATE: I have committed new tests for MergeJoin (which used to fail with
IllegalStateException with the old approach, and now pass fine).
--
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: commits-unsubscr...@calcite.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
