Composite aggregates

fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/combinatorics/EnumeratingIterable.java

@@ -44,6 +44,10 @@ static <T> EnumeratingIterable<T> singleIterable(@Nonnull final T singleElement)
         return new SingleIterable<>(singleElement);
     }
 
+    static <T> EnumeratingIterable<T> emptyOnEmptyIterable() {
+        return new SingleIterable<>();
+    }
+
     /**
      * An implementation of {@link EnumeratingIterable} that is optimized to work for empty
      * input sets.
@@ -84,13 +88,17 @@ public EnumeratingIterator<T> iterator() {
      * @param <T> type
      */
     class SingleIterable<T> implements EnumeratingIterable<T> {
-        @Nonnull
+        @Nullable
         private final T singleElement;
 
         private SingleIterable(@Nonnull final T singleElement) {
             this.singleElement = singleElement;
         }
 
+        private SingleIterable() {
+            this.singleElement = null;
+        }
+
         @Nonnull
         @Override
         public EnumeratingIterator<T> iterator() {
@@ -103,12 +111,12 @@ public EnumeratingIterator<T> iterator() {
      * @param <T> type of the element
      */
     class SingleIterator<T> extends AbstractIterator<List<T>> implements EnumeratingIterator<T> {
-        @Nonnull
+        @Nullable
         private final T singleElement;
 
         boolean atFirst = true;
 
-        private SingleIterator(@Nonnull final T singleElement) {
+        private SingleIterator(@Nullable final T singleElement) {
             this.singleElement = singleElement;
         }
 
@@ -128,6 +136,9 @@ protected List<T> computeNext() {
 
             atFirst = false;
 
+            if (singleElement == null) {
+                return ImmutableList.of();
+            }
             return ImmutableList.of(singleElement);
         }
     }

fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/combinatorics/TopologicalSort.java

@@ -537,10 +537,6 @@ public static <T, P> Iterable<List<T>> satisfyingPermutations(@Nonnull final Par
                                                                   @Nonnull final List<P> targetPermutation,
                                                                   @Nonnull final Function<T, P> domainMapper,
                                                                   @Nonnull final Function<List<T>, Integer> satisfiabilityFunction) {
-        if (partiallyOrderedSet.isEmpty()) {
-            return ImmutableList.of();
-        }
-
         if (partiallyOrderedSet.size() < targetPermutation.size()) {
             return ImmutableList.of();
         }
@@ -565,9 +561,11 @@ protected Iterator<T> domain(final int t) {
                     }
                 }
             };
-        } else {
-            Verify.verify(partiallyOrderedSet.size() == 1);
+        } else if (partiallyOrderedSet.size() == 1) {
             enumeratingIterator = EnumeratingIterable.singleIterable(Iterables.getOnlyElement(partiallyOrderedSet.getSet())).iterator();
+        } else {
+            Verify.verify(partiallyOrderedSet.isEmpty());
+            enumeratingIterator = EnumeratingIterable.<T>emptyOnEmptyIterable().iterator();
         }
 
         return () -> new AbstractIterator<>() {

fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/QueryPlanConstraint.java

@@ -62,6 +62,10 @@ public QueryPredicate getPredicate() {
         return predicate;
     }
 
+    public boolean isTautology() {
+        return predicate.isTautology();
+    }
+
     public boolean isConstrained() {
         return !getPredicate().isTautology();
     }

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

@@ -34,6 +34,7 @@
 import com.apple.foundationdb.record.query.plan.cascades.expressions.SelectExpression;
 import com.apple.foundationdb.record.query.plan.cascades.predicates.Placeholder;
 import com.apple.foundationdb.record.query.plan.cascades.predicates.PredicateWithValueAndRanges;
+import com.apple.foundationdb.record.query.plan.cascades.values.AggregateValue;
 import com.apple.foundationdb.record.query.plan.cascades.values.ArithmeticValue;
 import com.apple.foundationdb.record.query.plan.cascades.values.CountValue;
 import com.apple.foundationdb.record.query.plan.cascades.values.EmptyValue;
@@ -57,10 +58,10 @@
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
 
@@ -72,7 +73,12 @@
 public class AggregateIndexExpansionVisitor extends KeyExpressionExpansionVisitor
                                             implements ExpansionVisitor<KeyExpressionExpansionVisitor.VisitorState> {
     @Nonnull
-    static final Supplier<Map<String, BuiltInFunction<? extends Value>>> aggregateMap = Suppliers.memoize(AggregateIndexExpansionVisitor::computeAggregateMap);
+    static final Supplier<Map<String, BuiltInFunction<? extends Value>>> aggregateMap =
+            Suppliers.memoize(AggregateIndexExpansionVisitor::computeAggregateMap);
+
+    @Nonnull
+    static final Supplier<Map<String, BuiltInFunction<? extends Value>>> rollUpAggregateMap =
+            Suppliers.memoize(AggregateIndexExpansionVisitor::computeRollUpAggregateMap);
 
     @Nonnull
     protected final Index index;
@@ -92,7 +98,8 @@ public class AggregateIndexExpansionVisitor extends KeyExpressionExpansionVisito
      * @param recordTypes The indexed record types.
      */
     public AggregateIndexExpansionVisitor(@Nonnull final Index index, @Nonnull final Collection<RecordType> recordTypes) {
-        Preconditions.checkArgument(IndexTypes.BITMAP_VALUE.equals(index.getType()) || aggregateMap.get().containsKey(index.getType()));
+        Preconditions.checkArgument(IndexTypes.BITMAP_VALUE.equals(index.getType()) ||
+                aggregateMap.get().containsKey(index.getType()));
         Preconditions.checkArgument(index.getRootExpression() instanceof GroupingKeyExpression);
         this.index = index;
         this.groupingKeyExpression = ((GroupingKeyExpression)index.getRootExpression());
@@ -139,9 +146,9 @@ public MatchCandidate expand(@Nonnull final Supplier<Quantifier.ForEach> baseQua
                 .addAll(groupByPlaceholders).build();
 
         // 3. construct SELECT-HAVING with SORT on top.
-        final var selectHavingAndPlaceholderAliases = constructSelectHaving(groupByQun, placeholders);
-        final var selectHaving = selectHavingAndPlaceholderAliases.getLeft();
-        final var placeHolderAliases = selectHavingAndPlaceholderAliases.getRight();
+        final var constructSelectHavingResult = constructSelectHaving(groupByQun, placeholders);
+        final var selectHaving = constructSelectHavingResult.getSelectExpression();
+        final var placeHolderAliases = constructSelectHavingResult.getPlaceholderAliases();
 
         // 4. add sort on top, if necessary, this will be absorbed later on as an ordering property of the match candidate.
         final var maybeWithSort = placeHolderAliases.isEmpty()
@@ -278,19 +285,25 @@ protected NonnullPair<Quantifier, List<Placeholder>> constructGroupBy(@Nonnull f
     }
 
     @Nonnull
-    private NonnullPair<SelectExpression, List<CorrelationIdentifier>> constructSelectHaving(@Nonnull final Quantifier groupByQun,
-                                                                                             @Nonnull final List<Placeholder> selectWherePlaceholders) {
+    private ConstructSelectHavingResult constructSelectHaving(@Nonnull final Quantifier groupByQun,
+                                                              @Nonnull final List<Placeholder> selectWherePlaceholders) {
+        final var rangesOverExpression = groupByQun.getRangesOver().get();
+        Verify.verify(rangesOverExpression instanceof GroupByExpression);
+        final var groupByExpression = (GroupByExpression)rangesOverExpression;
+
         // the grouping value in GroupByExpression comes first (if set).
         @Nullable final var groupingValueReference =
-                (groupByQun.getRangesOver().get() instanceof GroupByExpression && ((GroupByExpression)groupByQun.getRangesOver().get()).getGroupingValue() == null)
-                ? null
-                : FieldValue.ofOrdinalNumber(groupByQun.getFlowedObjectValue(), 0);
+                groupByExpression.getGroupingValue() == null
+                ? null : FieldValue.ofOrdinalNumber(groupByQun.getFlowedObjectValue(), 0);
 
-        final var aggregateValueReference = FieldValue.ofOrdinalNumberAndFuseIfPossible(FieldValue.ofOrdinalNumber(groupByQun.getFlowedObjectValue(), groupingValueReference == null ? 0 : 1), 0);
+        final var aggregateValueReference =
+                FieldValue.ofOrdinalNumberAndFuseIfPossible(FieldValue.ofOrdinalNumber(groupByQun.getFlowedObjectValue(),
+                        groupingValueReference == null ? 0 : 1), 0);
 
         final var placeholderAliases = ImmutableList.<CorrelationIdentifier>builder();
         final var selectHavingGraphExpansionBuilder = GraphExpansion.builder().addQuantifier(groupByQun);
-        final List<Value> groupingValues = groupingValueReference == null ? Collections.emptyList() : Values.deconstructRecord(groupingValueReference);
+        final List<Value> groupingValues = groupingValueReference == null
+                                           ? ImmutableList.of() : Values.deconstructRecord(groupingValueReference);
         if (groupingValueReference != null) {
             int i = 0;
             for (final var groupingValue : groupingValues) {
@@ -322,7 +335,15 @@ private NonnullPair<SelectExpression, List<CorrelationIdentifier>> constructSele
         } else {
             finalPlaceholders = placeholderAliases.build();
         }
-        return NonnullPair.of(selectHavingGraphExpansionBuilder.build().buildSelect(), finalPlaceholders);
+
+        return new ConstructSelectHavingResult(selectHavingGraphExpansionBuilder.build().buildSelect(),
+                finalPlaceholders);
+    }
+
+    @Nonnull
+    public static Optional<AggregateValue> aggregateValue(@Nonnull final Index index, @Nonnull final Value argument) {
+        return Optional.of((AggregateValue)aggregateMap.get()
+                .get(index.getType()).encapsulate(ImmutableList.of(argument)));
     }
 
     @Nonnull
@@ -339,4 +360,53 @@ private static Map<String, BuiltInFunction<? extends Value>> computeAggregateMap
         mapBuilder.put(IndexTypes.PERMUTED_MIN, new NumericAggregationValue.MinFn());
         return mapBuilder.build();
     }
+
+    public static boolean canBeRolledUp(@Nonnull final String indexType) {
+        return rollUpAggregateMap.get().containsKey(indexType);
+    }
+
+    @Nonnull
+    public static Optional<AggregateValue> rollUpAggregateValueMaybe(@Nonnull final String indexType, @Nonnull final Value argument) {
+        return Optional.ofNullable(rollUpAggregateMap.get()
+                .get(indexType))
+                .map(fn -> (AggregateValue)fn.encapsulate(ImmutableList.of(argument)));
+    }
+
+    @Nonnull
+    private static Map<String, BuiltInFunction<? extends Value>> computeRollUpAggregateMap() {
+        final ImmutableMap.Builder<String, BuiltInFunction<? extends Value>> mapBuilder = ImmutableMap.builder();
+        mapBuilder.put(IndexTypes.MAX_EVER_LONG, new NumericAggregationValue.MaxFn());
+        mapBuilder.put(IndexTypes.MIN_EVER_LONG, new NumericAggregationValue.MinFn());
+        mapBuilder.put(IndexTypes.MAX_EVER_TUPLE, new NumericAggregationValue.MaxFn());
+        mapBuilder.put(IndexTypes.MIN_EVER_TUPLE, new NumericAggregationValue.MinFn());
+        mapBuilder.put(IndexTypes.SUM, new NumericAggregationValue.SumFn());
+        mapBuilder.put(IndexTypes.COUNT, new NumericAggregationValue.SumFn());
+        mapBuilder.put(IndexTypes.COUNT_NOT_NULL, new NumericAggregationValue.SumFn());
+        mapBuilder.put(IndexTypes.PERMUTED_MAX, new NumericAggregationValue.MaxFn());
+        mapBuilder.put(IndexTypes.PERMUTED_MIN, new NumericAggregationValue.MinFn());
+        return mapBuilder.build();
+    }
+
+    private static class ConstructSelectHavingResult {
+        @Nonnull
+        private final SelectExpression selectExpression;
+        @Nonnull
+        private final List<CorrelationIdentifier> placeholderAliases;
+
+        private ConstructSelectHavingResult(@Nonnull final SelectExpression selectExpression,
+                                            @Nonnull final List<CorrelationIdentifier> placeholderAliases) {
+            this.selectExpression = selectExpression;
+            this.placeholderAliases = placeholderAliases;
+        }
+
+        @Nonnull
+        public SelectExpression getSelectExpression() {
+            return selectExpression;
+        }
+
+        @Nonnull
+        public List<CorrelationIdentifier> getPlaceholderAliases() {
+            return placeholderAliases;
+        }
+    }
 }