zabetak commented on code in PR #2966:
URL: https://github.com/apache/hive/pull/2966#discussion_r857739177
##########
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/HiveCalciteUtil.java:
##########
@@ -1257,15 +1249,26 @@ public Void visitCall(RexCall call) {
}
public boolean hasDisjunction(RexNode node) {
- // clear the state
- inNegation = false;
- hasDisjunction = false;
-
node.accept(this);
return hasDisjunction;
}
}
+ /**
+ * Find disjunction (OR) in an expression (at any level of nesting).
Review Comment:
`Find` implies that we are going to return a disjunctive expression.
Suggestion:
`Returns whether the expression has disjunctions (OR) at any level of
nesting.`
##########
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/HiveCalciteUtil.java:
##########
@@ -1257,15 +1249,26 @@ public Void visitCall(RexCall call) {
}
public boolean hasDisjunction(RexNode node) {
- // clear the state
- inNegation = false;
- hasDisjunction = false;
-
node.accept(this);
return hasDisjunction;
}
}
+ /**
+ * Find disjunction (OR) in an expression (at any level of nesting).
+ *
+ * Example 1: OR(=($0, $1), IS NOT NULL($2))):INTEGER (OR in the top-level
expression)
+ * Example 2: NOT(AND(=($0, $1), IS NOT NULL($2))
+ * this is equivalent to OR((<>($0, $1), IS NULL($2))
+ * Example 3: AND(OR(=($0, $1), IS NOT NULL($2)))) (OR in inner expression)
+ *
+ * @param node the expression where to look for disjunctions.
+ * @return true if the given expressions contains a disjunction, false
otherwise.
+ */
+ public static boolean hasDisjuction(RexNode node) {
+ return new DisjunctivePredicatesFinder().hasDisjunction(node);
Review Comment:
nit to get rid of the `DisjunctivePredicateFinder#hasDisjunction` method:
```
DisjunctivePredicateFinder finder = new DisjunctivePredicateFinder();
node.accept(finder);
return finder.hasDisjunction;
```
##########
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/HiveCalciteUtil.java:
##########
@@ -1214,6 +1214,58 @@ public FixNullabilityShuttle(RexBuilder rexBuilder,
}
}
+ /**
+ * Find disjunction (OR) in an expression (at any level of nesting).
+ *
+ * Example 1: OR(=($0, $1), IS NOT NULL($2))):INTEGER (OR in the top-level
expression)
+ * Example 2: NOT(AND(=($0, $1), IS NOT NULL($2))
+ * this is equivalent to OR((<>($0, $1), IS NULL($2))
+ * Example 3: AND(OR(=($0, $1), IS NOT NULL($2)))) (OR in inner expression)
+ */
Review Comment:
I had in mind compiling with `-Pjavadoc` profile and checking for new errors
in this class. Actually I am afraid of `<>` symbols as well as `$`. Don't
remember if it is fine to use them like that.
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