adjust binary partition rule to send predicates to a more ideal location

Author: alecgrieser

fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/rules/PartitionBinarySelectRule.java

@@ -95,12 +95,24 @@ public void onMatch(@Nonnull final ExplorationCascadesRuleCall call) {
 
         for (final var predicate : selectExpression.getPredicates()) {
             final var correlatedTo = predicate.getCorrelatedTo();
-            final var correlatedToRight = correlatedTo.contains(rightQuantifier.getAlias());
-
-            if (!rightDependsOnLeft || !correlatedToRight) {
-                leftPredicatesBuilder.add(predicate);
-            } else {
+            final var correlatedToLeft = correlatedTo.contains(leftAlias);
+            final var correlatedToRight = correlatedTo.contains(rightAlias);
+
+            if (correlatedToLeft && correlatedToRight) {
+                // Predicate correlated to both. If the left depends on the right, we need to send it
+                // to the left to avoid a circular dependency. Otherwise, we push it to the right
+                if (leftDependsOnRight) {
+                    leftPredicatesBuilder.add(predicate);
+                } else {
+                    rightPredicatesBuilder.add(predicate);
+                }
+            } else if (correlatedToRight) {
+                // Predicate is correlated to just the right. Send it to the right
                 rightPredicatesBuilder.add(predicate);
+            } else {
+                // Predicate is either correlated to just the left or it is correlated to neither.
+                // Send it to the left, as this is the left most position it can be
+                leftPredicatesBuilder.add(predicate);
             }
         }
 

fdb-record-layer-core/src/test/java/com/apple/foundationdb/record/query/plan/cascades/rules/PartitionBinarySelectRuleTest.java

@@ -213,7 +213,8 @@ void pushSimplePredicatesWithCorrelatedQuantifiers() {
 
         // Push the predicate on to the t quantifier and the predicate on g onto the g quantifier
         final Quantifier newT = forEach(selectWithPredicates(t, fieldPredicate(t, "b", new Comparisons.SimpleComparison(Comparisons.Type.EQUALS, "hello"))));
-        final Quantifier newG = forEach(selectWithPredicates(g, fieldPredicate(g, "two", new Comparisons.SimpleComparison(Comparisons.Type.EQUALS, "world"))));
+        final Quantifier newGLower = explodeField(newT, "g");
+        final Quantifier newG = forEach(selectWithPredicates(newGLower, fieldPredicate(newGLower, "two", new Comparisons.SimpleComparison(Comparisons.Type.EQUALS, "world"))));
         final SelectExpression newJoin = join(newT, newG)
                 .addResultColumn(projectColumn(newT, "a"))
                 .addResultColumn(projectColumn(newG, "one"))
@@ -267,8 +268,10 @@ void partitionPredicatesWithExists() {
         // Push the predicate on t down to t. Push the existential predicate to be on top of g
         final Quantifier newT = forEach(selectWithPredicates(t,
                 fieldPredicate(t, "b", new Comparisons.SimpleComparison(Comparisons.Type.EQUALS, "hello"))));
-        final Quantifier newG = forEach(new SelectExpression(RCV_OF_ONE, ImmutableList.of(g), ImmutableList.of(new ExistsPredicate(g.getAlias()))));
+        final Quantifier newGLower = Quantifier.existential(explodeField(newT, "g").getRangesOver());
+        final Quantifier newG = forEach(new SelectExpression(RCV_OF_ONE, ImmutableList.of(newGLower), ImmutableList.of(new ExistsPredicate(newGLower.getAlias()))));
         final SelectExpression newJoin = join(newT, newG)
+                .addResultColumn(projectColumn(newT, "a"))
                 .build().buildSelect();
 
         testHelper.assertYields(join, newJoin);
@@ -312,7 +315,8 @@ void partitionSelectWhenResultValueComesFromExplodedField() {
                 .build().buildSelect();
 
         final Quantifier newT = forEach(selectWithPredicates(t, fieldPredicate(t, "b", new Comparisons.SimpleComparison(Comparisons.Type.LESS_THAN, "hello"))));
-        final Quantifier newG = forEach(selectWithPredicates(g, fieldPredicate(g, "two", new Comparisons.SimpleComparison(Comparisons.Type.LESS_THAN, "world"))));
+        final Quantifier newGLower = explodeField(newT, "g");
+        final Quantifier newG = forEach(selectWithPredicates(newGLower, fieldPredicate(newGLower, "two", new Comparisons.SimpleComparison(Comparisons.Type.LESS_THAN, "world"))));
         final SelectExpression newJoin = join(newT, newG)
                 .addResultColumn(projectColumn(newG, "one"))
                 .build().buildSelect();