Exemplo n.º 1
0
    @Override
    public PlanNode rewriteAggregation(
        AggregationNode node,
        Expression inheritedPredicate,
        PlanRewriter<Expression> planRewriter) {
      EqualityInference equalityInference = createEqualityInference(inheritedPredicate);

      List<Expression> pushdownConjuncts = new ArrayList<>();
      List<Expression> postAggregationConjuncts = new ArrayList<>();

      // Strip out non-deterministic conjuncts
      postAggregationConjuncts.addAll(
          ImmutableList.copyOf(filter(extractConjuncts(inheritedPredicate), not(deterministic()))));
      inheritedPredicate = stripNonDeterministicConjuncts(inheritedPredicate);

      // Sort non-equality predicates by those that can be pushed down and those that cannot
      for (Expression conjunct : EqualityInference.nonInferrableConjuncts(inheritedPredicate)) {
        Expression rewrittenConjunct =
            equalityInference.rewriteExpression(conjunct, in(node.getGroupBy()));
        if (rewrittenConjunct != null) {
          pushdownConjuncts.add(rewrittenConjunct);
        } else {
          postAggregationConjuncts.add(conjunct);
        }
      }

      // Add the equality predicates back in
      EqualityInference.EqualityPartition equalityPartition =
          equalityInference.generateEqualitiesPartitionedBy(in(node.getGroupBy()));
      pushdownConjuncts.addAll(equalityPartition.getScopeEqualities());
      postAggregationConjuncts.addAll(equalityPartition.getScopeComplementEqualities());
      postAggregationConjuncts.addAll(equalityPartition.getScopeStraddlingEqualities());

      PlanNode rewrittenSource =
          planRewriter.rewrite(node.getSource(), combineConjuncts(pushdownConjuncts));

      PlanNode output = node;
      if (rewrittenSource != node.getSource()) {
        output =
            new AggregationNode(
                node.getId(),
                rewrittenSource,
                node.getGroupBy(),
                node.getAggregations(),
                node.getFunctions(),
                node.getMasks(),
                node.getStep(),
                node.getSampleWeight(),
                node.getConfidence());
      }
      if (!postAggregationConjuncts.isEmpty()) {
        output =
            new FilterNode(
                idAllocator.getNextId(), output, combineConjuncts(postAggregationConjuncts));
      }
      return output;
    }
Exemplo n.º 2
0
    @Override
    public PlanNode rewriteSemiJoin(
        SemiJoinNode node, Expression inheritedPredicate, PlanRewriter<Expression> planRewriter) {
      Expression sourceEffectivePredicate = EffectivePredicateExtractor.extract(node.getSource());

      List<Expression> sourceConjuncts = new ArrayList<>();
      List<Expression> filteringSourceConjuncts = new ArrayList<>();
      List<Expression> postJoinConjuncts = new ArrayList<>();

      // TODO: see if there are predicates that can be inferred from the semi join output

      // Push inherited and source predicates to filtering source via a contrived join predicate
      // (but needs to avoid touching NULL values in the filtering source)
      Expression joinPredicate =
          equalsExpression(node.getSourceJoinSymbol(), node.getFilteringSourceJoinSymbol());
      EqualityInference joinInference =
          createEqualityInference(inheritedPredicate, sourceEffectivePredicate, joinPredicate);
      for (Expression conjunct :
          Iterables.concat(
              EqualityInference.nonInferrableConjuncts(inheritedPredicate),
              EqualityInference.nonInferrableConjuncts(sourceEffectivePredicate))) {
        Expression rewrittenConjunct =
            joinInference.rewriteExpression(conjunct, equalTo(node.getFilteringSourceJoinSymbol()));
        if (rewrittenConjunct != null && DeterminismEvaluator.isDeterministic(rewrittenConjunct)) {
          // Alter conjunct to include an OR filteringSourceJoinSymbol IS NULL disjunct
          Expression rewrittenConjunctOrNull =
              expressionOrNullSymbols(equalTo(node.getFilteringSourceJoinSymbol()))
                  .apply(rewrittenConjunct);
          filteringSourceConjuncts.add(rewrittenConjunctOrNull);
        }
      }
      EqualityInference.EqualityPartition joinInferenceEqualityPartition =
          joinInference.generateEqualitiesPartitionedBy(
              equalTo(node.getFilteringSourceJoinSymbol()));
      filteringSourceConjuncts.addAll(
          ImmutableList.copyOf(
              transform(
                  joinInferenceEqualityPartition.getScopeEqualities(),
                  expressionOrNullSymbols(equalTo(node.getFilteringSourceJoinSymbol())))));

      // Push inheritedPredicates down to the source if they don't involve the semi join output
      EqualityInference inheritedInference = createEqualityInference(inheritedPredicate);
      for (Expression conjunct : EqualityInference.nonInferrableConjuncts(inheritedPredicate)) {
        Expression rewrittenConjunct =
            inheritedInference.rewriteExpression(conjunct, in(node.getSource().getOutputSymbols()));
        // Since each source row is reflected exactly once in the output, ok to push
        // non-deterministic predicates down
        if (rewrittenConjunct != null) {
          sourceConjuncts.add(rewrittenConjunct);
        } else {
          postJoinConjuncts.add(conjunct);
        }
      }

      // Add the inherited equality predicates back in
      EqualityInference.EqualityPartition equalityPartition =
          inheritedInference.generateEqualitiesPartitionedBy(
              in(node.getSource().getOutputSymbols()));
      sourceConjuncts.addAll(equalityPartition.getScopeEqualities());
      postJoinConjuncts.addAll(equalityPartition.getScopeComplementEqualities());
      postJoinConjuncts.addAll(equalityPartition.getScopeStraddlingEqualities());

      PlanNode rewrittenSource =
          planRewriter.rewrite(node.getSource(), combineConjuncts(sourceConjuncts));
      PlanNode rewrittenFilteringSource =
          planRewriter.rewrite(
              node.getFilteringSource(), combineConjuncts(filteringSourceConjuncts));

      PlanNode output = node;
      if (rewrittenSource != node.getSource()
          || rewrittenFilteringSource != node.getFilteringSource()) {
        output =
            new SemiJoinNode(
                node.getId(),
                rewrittenSource,
                rewrittenFilteringSource,
                node.getSourceJoinSymbol(),
                node.getFilteringSourceJoinSymbol(),
                node.getSemiJoinOutput());
      }
      if (!postJoinConjuncts.isEmpty()) {
        output =
            new FilterNode(idAllocator.getNextId(), output, combineConjuncts(postJoinConjuncts));
      }
      return output;
    }
Exemplo n.º 3
0
    private OuterJoinPushDownResult processOuterJoin(
        Expression inheritedPredicate,
        Expression outerEffectivePredicate,
        Expression innerEffectivePredicate,
        Expression joinPredicate,
        Collection<Symbol> outerSymbols) {
      checkArgument(
          Iterables.all(
              DependencyExtractor.extractUnique(outerEffectivePredicate), in(outerSymbols)),
          "outerEffectivePredicate must only contain symbols from outerSymbols");
      checkArgument(
          Iterables.all(
              DependencyExtractor.extractUnique(innerEffectivePredicate), not(in(outerSymbols))),
          "innerEffectivePredicate must not contain symbols from outerSymbols");

      ImmutableList.Builder<Expression> outerPushdownConjuncts = ImmutableList.builder();
      ImmutableList.Builder<Expression> innerPushdownConjuncts = ImmutableList.builder();
      ImmutableList.Builder<Expression> postJoinConjuncts = ImmutableList.builder();

      // Strip out non-deterministic conjuncts
      postJoinConjuncts.addAll(filter(extractConjuncts(inheritedPredicate), not(deterministic())));
      inheritedPredicate = stripNonDeterministicConjuncts(inheritedPredicate);

      outerEffectivePredicate = stripNonDeterministicConjuncts(outerEffectivePredicate);
      innerEffectivePredicate = stripNonDeterministicConjuncts(innerEffectivePredicate);
      joinPredicate = stripNonDeterministicConjuncts(joinPredicate);

      // Generate equality inferences
      EqualityInference inheritedInference = createEqualityInference(inheritedPredicate);
      EqualityInference outerInference =
          createEqualityInference(inheritedPredicate, outerEffectivePredicate);

      EqualityInference.EqualityPartition equalityPartition =
          inheritedInference.generateEqualitiesPartitionedBy(in(outerSymbols));
      Expression outerOnlyInheritedEqualities =
          combineConjuncts(equalityPartition.getScopeEqualities());
      EqualityInference potentialNullSymbolInference =
          createEqualityInference(
              outerOnlyInheritedEqualities,
              outerEffectivePredicate,
              innerEffectivePredicate,
              joinPredicate);
      EqualityInference potentialNullSymbolInferenceWithoutInnerInferred =
          createEqualityInference(
              outerOnlyInheritedEqualities, outerEffectivePredicate, joinPredicate);

      // Sort through conjuncts in inheritedPredicate that were not used for inference
      for (Expression conjunct : EqualityInference.nonInferrableConjuncts(inheritedPredicate)) {
        Expression outerRewritten = outerInference.rewriteExpression(conjunct, in(outerSymbols));
        if (outerRewritten != null) {
          outerPushdownConjuncts.add(outerRewritten);

          // A conjunct can only be pushed down into an inner side if it can be rewritten in terms
          // of the outer side
          Expression innerRewritten =
              potentialNullSymbolInference.rewriteExpression(outerRewritten, not(in(outerSymbols)));
          if (innerRewritten != null) {
            innerPushdownConjuncts.add(innerRewritten);
          }
        } else {
          postJoinConjuncts.add(conjunct);
        }
      }

      // See if we can push down any outer or join predicates to the inner side
      for (Expression conjunct :
          EqualityInference.nonInferrableConjuncts(and(outerEffectivePredicate, joinPredicate))) {
        Expression rewritten =
            potentialNullSymbolInference.rewriteExpression(conjunct, not(in(outerSymbols)));
        if (rewritten != null) {
          innerPushdownConjuncts.add(rewritten);
        }
      }

      // TODO: consider adding join predicate optimizations to outer joins

      // Add the equalities from the inferences back in
      outerPushdownConjuncts.addAll(equalityPartition.getScopeEqualities());
      postJoinConjuncts.addAll(equalityPartition.getScopeComplementEqualities());
      postJoinConjuncts.addAll(equalityPartition.getScopeStraddlingEqualities());
      innerPushdownConjuncts.addAll(
          potentialNullSymbolInferenceWithoutInnerInferred
              .generateEqualitiesPartitionedBy(not(in(outerSymbols)))
              .getScopeEqualities());

      return new OuterJoinPushDownResult(
          combineConjuncts(outerPushdownConjuncts.build()),
          combineConjuncts(innerPushdownConjuncts.build()),
          combineConjuncts(postJoinConjuncts.build()));
    }