mihaibudiu commented on code in PR #3921:
URL: https://github.com/apache/calcite/pull/3921#discussion_r1723948664
##########
core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java:
##########
@@ -2169,57 +2145,155 @@ public static boolean equalType(String desc0,
MutableRel rel0, String desc1,
}
/**
- * Check if filter under join can be pulled up,
+ * Check if calc under join can be pulled up,
* when meeting JoinOnCalc of query unify to Join of target.
* Working in rules: {@link JoinOnLeftCalcToJoinUnifyRule} <br/>
* {@link JoinOnRightCalcToJoinUnifyRule} <br/>
* {@link JoinOnCalcsToJoinUnifyRule} <br/>
*/
- private static boolean canPullUpFilterUnderJoin(JoinRelType joinType,
- @Nullable RexNode leftFilterRexNode, @Nullable RexNode
rightFilterRexNode) {
- if (joinType == JoinRelType.INNER) {
- return true;
- }
- if (joinType == JoinRelType.LEFT
- && (rightFilterRexNode == null || rightFilterRexNode.isAlwaysTrue())) {
- return true;
- }
- if (joinType == JoinRelType.RIGHT
- && (leftFilterRexNode == null || leftFilterRexNode.isAlwaysTrue())) {
- return true;
+ private static boolean canPullUpCalcUnderJoin(JoinRelType joinType,
+ @Nullable Pair<RexNode, List<RexNode>> qInput0Explained,
+ @Nullable Pair<RexNode, List<RexNode>> qInput1Explained) {
+ if (qInput0Explained != null
+ && joinType.generatesNullsOn(0)
+ && !isCalcStrong(qInput0Explained)) {
+ return false;
}
- if (joinType == JoinRelType.FULL
- && ((rightFilterRexNode == null || rightFilterRexNode.isAlwaysTrue())
- && (leftFilterRexNode == null || leftFilterRexNode.isAlwaysTrue()))) {
- return true;
+ if (qInput1Explained != null
+ && joinType.generatesNullsOn(1)
+ && !isCalcStrong(qInput1Explained)) {
+ return false;
}
- return false;
+ return true;
+ }
+
+ /** Determines if all projects are strong and the condition is always true.
*/
+ private static boolean isCalcStrong(Pair<RexNode, List<RexNode>>
inputExplained) {
+ final RexNode cond = requireNonNull(inputExplained.left, "condition");
+ final List<RexNode> projs = requireNonNull(inputExplained.right,
"projects");
+ return cond.isAlwaysTrue() && projs.stream().allMatch(STRONG::isNull);
}
/**
- * Check if project under join can be pulled up,
- * when meeting JoinOnCalc of query unify to Join of target.
+
+ */
+
+ /**
+ * Generates project expressions by shifting and adjusting the nullability
of expressions
+ * based on the provided join targets and inputs.
+ *
+ * <p>Used in the Join rewrite to pull up the calc in query
+ * to the join in mv to ensure operator equivalence. (Already make sure that
pull up is valid).
* Working in rules: {@link JoinOnLeftCalcToJoinUnifyRule} <br/>
* {@link JoinOnRightCalcToJoinUnifyRule} <br/>
* {@link JoinOnCalcsToJoinUnifyRule} <br/>
+ *
+ * @param query MutableRel of query
+ * @param target MutableRel of target
Review Comment:
Ideally that google doc would be posted somewhere publicly and linked from
the code here.
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