alex-plekhanov commented on code in PR #11972:
URL: https://github.com/apache/ignite/pull/11972#discussion_r2030955054
##########
modules/calcite/src/main/java/org/apache/ignite/internal/processors/query/calcite/prepare/IgnitePlanner.java:
##########
@@ -586,6 +590,117 @@ private RelNode
visitLeftAndRightCorrelateHands(LogicalCorrelate correlate, Corr
return relShuttle.visit(rel);
}
+ /**
+ * Due to distributive property of conjunction over disjunction we can
extract common part of conjunctions.
+ * This can help us to simplify and push down filters.
+ * For example, condition:
+ * (a = 0 and x = 1) or (a = 0 and y = 2) or (a = 0 and z = 3)
+ * can be translated to:
+ * a = 0 and (x = 1 or y = 2 or z = 3)
+ * after such a transformation condition "a = 0" can be used as index
access predicate.
+ */
+ public RelNode extractConjunctionOverDisjunctionCommonPart(RelNode rel) {
+ return new RelHomogeneousShuttle() {
+ /** {@inheritDoc} */
+ @Override public RelNode visit(LogicalFilter filter) {
+ RexNode condition =
transform(filter.getCluster().getRexBuilder(), filter.getCondition());
+
+ if (condition != filter.getCondition())
+ filter = filter.copy(filter.getTraitSet(),
filter.getInput(), condition);
+
+ return super.visit(filter);
+ }
+
+ /** {@inheritDoc} */
+ @Override public RelNode visit(LogicalJoin join) {
+ RexNode condition =
transform(join.getCluster().getRexBuilder(), join.getCondition());
+
+ if (condition != join.getCondition()) {
+ join = join.copy(join.getTraitSet(), condition,
join.getLeft(), join.getRight(),
+ join.getJoinType(), join.isSemiJoinDone());
+ }
+
+ return super.visit(join);
+ }
+
+ /** */
+ private RexNode transform(RexBuilder rexBuilder, RexNode
condition) {
+ // It makes sence to extract only top level disjunction common
part.
+ if (!condition.isA(SqlKind.OR))
+ return condition;
+
+ Set<RexNode> commonPart = new HashSet<>();
+
+ List<RexNode> orOps = ((RexCall)condition).getOperands();
+
+ RexNode firstOp = orOps.get(0);
+
+ for (RexNode andOpFirst : conjunctionOperands(firstOp)) {
+ boolean found = false;
+
+ for (int i = 1; i < orOps.size(); i++) {
+ found = false;
+
+ for (RexNode andOpOther :
conjunctionOperands(orOps.get(i))) {
+ if (andOpFirst.equals(andOpOther)) {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found)
+ break;
+ }
+
+ if (found)
+ commonPart.add(andOpFirst);
+ }
+
+ if (commonPart.isEmpty())
+ return condition;
+
+ List<RexNode> newOrOps = new ArrayList<>(orOps.size());
+
+ for (RexNode orOp : orOps) {
+ List<RexNode> newAndOps = new ArrayList<>();
+
+ for (RexNode andOp : conjunctionOperands(orOp)) {
+ if (!commonPart.contains(andOp))
+ newAndOps.add(andOp);
+ }
+
+ if (!newAndOps.isEmpty()) {
+ RexNode newAnd =
RexUtil.composeConjunction(rexBuilder, newAndOps);
Review Comment:
Almos all tests in `testExtractCommonDisjunctionPart` have `newOrOps.size()
> 1`. "Three operands disjunction" has `newOrOps.size() == 3`, for example.
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