vineetgarg02 commented on a change in pull request #970: Hive 23100
URL: https://github.com/apache/hive/pull/970#discussion_r407815212
##########
File path:
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/HiveCalciteUtil.java
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@@ -1157,4 +1174,126 @@ public Void visitInputRef(RexInputRef inputRef) {
return inputRefSet;
}
}
+
+ /** Fixes up the type of all {@link RexInputRef}s in an
+ * expression to match differences in nullability.
+ *
+ * <p>Throws if there any greater inconsistencies of type. */
+ public static List<RexNode> fixNullability(final RexBuilder rexBuilder,
+ List<RexNode> nodes, final List<RelDataType> fieldTypes) {
+ return new FixNullabilityShuttle(rexBuilder, fieldTypes).apply(nodes);
+ }
+
+ /** Fixes up the type of all {@link RexInputRef}s in an
+ * expression to match differences in nullability.
+ *
+ * <p>Throws if there any greater inconsistencies of type. */
+ public static RexNode fixNullability(final RexBuilder rexBuilder,
+ RexNode node, final List<RelDataType> fieldTypes) {
+ return new FixNullabilityShuttle(rexBuilder, fieldTypes).apply(node);
+ }
+
+ /** Shuttle that fixes up an expression to match changes in nullability of
+ * input fields. */
+ public static class FixNullabilityShuttle extends RexShuttle {
+ private final List<RelDataType> typeList;
+ private final RexBuilder rexBuilder;
+
+ public FixNullabilityShuttle(RexBuilder rexBuilder,
+ List<RelDataType> typeList) {
+ this.typeList = typeList;
+ this.rexBuilder = rexBuilder;
+ }
+
+ @Override public RexNode visitInputRef(RexInputRef ref) {
+ final RelDataType rightType = typeList.get(ref.getIndex());
+ final RelDataType refType = ref.getType();
+ if (refType == rightType) {
+ return ref;
+ }
+ final RelDataType refType2 =
+ rexBuilder.getTypeFactory().createTypeWithNullability(refType,
+ rightType.isNullable());
+ // This is a validation check which can become quite handy debugging type
+ // issues. Basically, we need both types to be equal, only difference
should
+ // be nullability.
+ // However, we make an exception for Hive wrt CHAR type because Hive
encodes
+ // the STRING type for literals within CHAR value (see {@link
HiveNlsString})
+ // while Calcite always considers these literals to be a CHAR, which
means
+ // that the reference may be created as a STRING or VARCHAR from AST node
+ // at parsing time but the actual type referenced is a CHAR.
+ if (refType2 == rightType) {
+ return new RexInputRef(ref.getIndex(), refType2);
+ } else if (refType2.getFamily() == SqlTypeFamily.CHARACTER &&
+ rightType.getSqlTypeName() == SqlTypeName.CHAR &&
!rightType.isNullable()) {
+ return new RexInputRef(ref.getIndex(), rightType);
+ }
+ throw new AssertionError("mismatched type " + ref + " " + rightType);
+ }
+ }
+
+ /**
+ * The method tries to rewrite an IN function call into an OR/AND function
call.
+ * For instance:
+ * <pre>
+ * (c) IN ( v1, v2, ...) => c=v1 || c=v2 || ...
+ * </pre>
+ * Or:
+ * <pre>
+ * (c,d) IN ( (v1,v2), (v3,v4), ...) => (c=v1 && d=v2) || (c=v3 && d=v4)
|| ...
+ * </pre>
+ *
+ * Returns null if the transformation fails, e.g., when non-deterministic
+ * calls are found in the expressions.
+ */
+ public static List<RexNode> transformIntoOrAndClause(List<RexNode> operands,
RexBuilder rexBuilder) {
+ final List<RexNode> disjuncts = new ArrayList<>(operands.size() - 2);
Review comment:
Nit - This doesn't really convert IN expressions into OR but a list of
expressions into OR.
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