Java Code Examples for org.apache.calcite.rel.core.Aggregate#getInput()

/**
 * Infers predicates for an Aggregate.
 *
 * <p>Pulls up predicates that only contains references to columns in the
 * GroupSet. For e.g.
 *
 * <blockquote><pre>
 * inputPullUpExprs : { a &gt; 7, b + c &lt; 10, a + e = 9}
 * groupSet         : { a, b}
 * pulledUpExprs    : { a &gt; 7}
 * </pre></blockquote>
 */
public RelOptPredicateList getPredicates(Aggregate agg, RelMetadataQuery mq) {
  final RelNode input = agg.getInput();
  final RexBuilder rexBuilder = agg.getCluster().getRexBuilder();
  final RelOptPredicateList inputInfo = mq.getPulledUpPredicates(input);
  final List<RexNode> aggPullUpPredicates = new ArrayList<>();

  ImmutableBitSet groupKeys = agg.getGroupSet();
  if (groupKeys.isEmpty()) {
    // "GROUP BY ()" can convert an empty relation to a non-empty relation, so
    // it is not valid to pull up predicates. In particular, consider the
    // predicate "false": it is valid on all input rows (trivially - there are
    // no rows!) but not on the output (there is one row).
    return RelOptPredicateList.EMPTY;
  }
  Mapping m = Mappings.create(MappingType.PARTIAL_FUNCTION,
      input.getRowType().getFieldCount(), agg.getRowType().getFieldCount());

  int i = 0;
  for (int j : groupKeys) {
    m.set(j, i++);
  }

  for (RexNode r : inputInfo.pulledUpPredicates) {
    ImmutableBitSet rCols = RelOptUtil.InputFinder.bits(r);
    if (groupKeys.contains(rCols)) {
      r = r.accept(new RexPermuteInputsShuttle(m, input));
      aggPullUpPredicates.add(r);
    }
  }
  return RelOptPredicateList.of(rexBuilder, aggPullUpPredicates);
}
 

/** @see #dispatch */
public Result visit(Aggregate e) {
  // "select a, b, sum(x) from ( ... ) group by a, b"
  final Result x = visitChild(0, e.getInput());
  final Builder builder;
  if (e.getInput() instanceof Project) {
    builder = x.builder(e);
    builder.clauses.add(Clause.GROUP_BY);
  } else {
    builder = x.builder(e, Clause.GROUP_BY);
  }
  List<SqlNode> groupByList = FluentListUtils.list();
  final List<SqlNode> selectList = new ArrayList<>();
  for (int group : e.getGroupSet()) {
    final SqlNode field = builder.context.field(group);
    addSelect(selectList, field, e.getRowType());
    groupByList.add(field);
  }
  for (AggregateCall aggCall : e.getAggCallList()) {
    SqlNode aggCallSqlNode = builder.context.toSql(aggCall);
    if (aggCall.getAggregation() instanceof SqlSingleValueAggFunction) {
      aggCallSqlNode = dialect.
          rewriteSingleValueExpr(aggCallSqlNode);
    }
    addSelect(selectList, aggCallSqlNode, e.getRowType());
  }
  builder.setSelect(new SqlNodeList(selectList, POS));
  if (!groupByList.isEmpty() || e.getAggCallList().isEmpty()) {
    // Some databases don't support "GROUP BY ()". We can omit it as long
    // as there is at least one aggregate function.
    builder.setGroupBy(new SqlNodeList(groupByList, POS));
  }
  return builder.result();
}
 

/**
 * @see #dispatch
 */
public Result visit(Aggregate e) {
  // "select a, b, sum(x) from ( ... ) group by a, b"
  final Result x = visitChild(0, e.getInput());
  final Builder builder;
  if (e.getInput() instanceof Project) {
    builder = x.builder(e);
    builder.clauses.add(Clause.GROUP_BY);
  } else {
    builder = x.builder(e, Clause.GROUP_BY);
  }
  List<SqlNode> groupByList = Expressions.list();
  final List<SqlNode> selectList = new ArrayList<>();
  for (int group : e.getGroupSet()) {
    final SqlNode field = builder.context.field(group);
    addSelect(selectList, field, e.getRowType());
    groupByList.add(field);
  }
  for (AggregateCall aggCall : e.getAggCallList()) {
    SqlNode aggCallSqlNode = builder.context.toSql(aggCall);
    if (aggCall.getAggregation() instanceof SqlSingleValueAggFunction) {
      aggCallSqlNode = dialect.
        rewriteSingleValueExpr(aggCallSqlNode);
    }
    addSelect(selectList, aggCallSqlNode, e.getRowType());
  }
  builder.setSelect(new SqlNodeList(selectList, POS));
  if (!groupByList.isEmpty() || e.getAggCallList().isEmpty()) {
    // Some databases don't support "GROUP BY ()". We can omit it as long
    // as there is at least one aggregate function.
    builder.setGroupBy(new SqlNodeList(groupByList, POS));
  }
  return builder.result();
}
 

/**
 * Pushes a {@link org.apache.calcite.rel.core.Filter}
 * past a {@link org.apache.calcite.rel.core.Aggregate}.
 */
RelNode filterAggregateTranspose(RelOptRuleCall call,
                                 Filter filterRel,
                                 Aggregate aggRel) {
  final List<RexNode> conditions =
      RelOptUtil.conjunctions(filterRel.getCondition());
  final RexBuilder rexBuilder = filterRel.getCluster().getRexBuilder();
  final List<RelDataTypeField> origFields =
      aggRel.getRowType().getFieldList();
  final int[] adjustments = new int[origFields.size()];
  int i = 0;
  for (int key : aggRel.getGroupSet()) {
    adjustments[i] = key - i;
    i++;
  }
  final List<RexNode> pushedConditions = Lists.newArrayList();

  for (RexNode condition : conditions) {
    ImmutableBitSet rCols = RelOptUtil.InputFinder.bits(condition);
    if (canPush(aggRel, rCols)) {
      pushedConditions.add(
          condition.accept(
              new RelOptUtil.RexInputConverter(rexBuilder, origFields,
                  aggRel.getInput(0).getRowType().getFieldList(),
                  adjustments)));
    } else {
      return null;
    }
  }

  final RelBuilder builder = call.builder();
  RelNode rel =
      builder.push(aggRel.getInput()).filter(pushedConditions).build();
  if (rel == aggRel.getInput(0)) {
    return null;
  }
  rel = aggRel.copy(aggRel.getTraitSet(), ImmutableList.of(rel));
  return rel;
}
 

/**
 * Infers predicates for an Aggregate.
 *
 * <p>Pulls up predicates that only contains references to columns in the
 * GroupSet. For e.g.
 *
 * <blockquote><pre>
 * inputPullUpExprs : { a &gt; 7, b + c &lt; 10, a + e = 9}
 * groupSet         : { a, b}
 * pulledUpExprs    : { a &gt; 7}
 * </pre></blockquote>
 */
public RelOptPredicateList getPredicates(Aggregate agg, RelMetadataQuery mq) {
  final RelNode input = agg.getInput();
  final RexBuilder rexBuilder = agg.getCluster().getRexBuilder();
  final RelOptPredicateList inputInfo = mq.getPulledUpPredicates(input);
  final List<RexNode> aggPullUpPredicates = new ArrayList<>();

  ImmutableBitSet groupKeys = agg.getGroupSet();
  if (groupKeys.isEmpty()) {
    // "GROUP BY ()" can convert an empty relation to a non-empty relation, so
    // it is not valid to pull up predicates. In particular, consider the
    // predicate "false": it is valid on all input rows (trivially - there are
    // no rows!) but not on the output (there is one row).
    return RelOptPredicateList.EMPTY;
  }
  Mapping m = Mappings.create(MappingType.PARTIAL_FUNCTION,
      input.getRowType().getFieldCount(), agg.getRowType().getFieldCount());

  int i = 0;
  for (int j : groupKeys) {
    m.set(j, i++);
  }

  for (RexNode r : inputInfo.pulledUpPredicates) {
    ImmutableBitSet rCols = RelOptUtil.InputFinder.bits(r);
    if (groupKeys.contains(rCols)) {
      r = r.accept(new RexPermuteInputsShuttle(m, input));
      aggPullUpPredicates.add(r);
    }
  }
  return RelOptPredicateList.of(rexBuilder, aggPullUpPredicates);
}
 

/**
 * Returns an input with the same row type with the input Aggregate,
 * create a Project node if needed.
 */
private RelNode getInputWithSameRowType(Aggregate bottomAggRel) {
  if (RelOptUtil.areRowTypesEqual(
          bottomAggRel.getRowType(),
          bottomAggRel.getInput(0).getRowType(),
          false)) {
    return bottomAggRel.getInput(0);
  } else {
    return RelOptUtil.createProject(
        bottomAggRel.getInput(),
        bottomAggRel.getGroupSet().asList());
  }
}
 

private Result visitAggregate(Aggregate e, List<Integer> groupKeyList) {
  // "select a, b, sum(x) from ( ... ) group by a, b"
  final Result x = visitChild(0, e.getInput());
  final Builder builder;
  if (e.getInput() instanceof Project) {
    builder = x.builder(e);
    builder.clauses.add(Clause.GROUP_BY);
  } else {
    builder = x.builder(e, Clause.GROUP_BY);
  }
  final List<SqlNode> selectList = new ArrayList<>();
  final List<SqlNode> groupByList =
      generateGroupList(builder, selectList, e, groupKeyList);
  return buildAggregate(e, builder, selectList, groupByList);
}
 

@Override
protected RelNode rewriteQuery(RelBuilder relBuilder, RexBuilder rexBuilder, RexSimplify simplify,
        RelMetadataQuery mq, RexNode compensationColumnsEquiPred, RexNode otherCompensationPred,
        Project topProject, RelNode node, BiMap<RelTableRef, RelTableRef> queryToViewTableMapping,
        EquivalenceClasses viewEC, EquivalenceClasses queryEC) {
    Aggregate aggregate = (Aggregate) node;

    // Our target node is the node below the root, which should have the maximum
    // number of available expressions in the tree in order to maximize our
    // number of rewritings.
    // If the program is available, we execute it to maximize rewriting opportunities.
    // For instance, a program might pull up all the expressions that are below the
    // aggregate so we can introduce compensation filters easily. This is important
    // depending on the planner strategy.
    RelNode newAggregateInput = aggregate.getInput(0);
    RelNode target = aggregate.getInput(0);
    if (unionRewritingPullProgram != null) {
        final HepPlanner tmpPlanner = new HepPlanner(unionRewritingPullProgram);
        tmpPlanner.setRoot(newAggregateInput);
        newAggregateInput = tmpPlanner.findBestExp();
        target = newAggregateInput.getInput(0);
    }

    // We need to check that all columns required by compensating predicates
    // are contained in the query.
    List<RexNode> queryExprs = extractReferences(rexBuilder, target);
    if (!compensationColumnsEquiPred.isAlwaysTrue()) {
        compensationColumnsEquiPred = rewriteExpression(rexBuilder, mq, target, target, queryExprs,
                queryToViewTableMapping, queryEC, false, compensationColumnsEquiPred);
        if (compensationColumnsEquiPred == null) {
            // Skip it
            return null;
        }
    }
    // For the rest, we use the query equivalence classes
    if (!otherCompensationPred.isAlwaysTrue()) {
        otherCompensationPred = rewriteExpression(rexBuilder, mq, target, target, queryExprs,
                queryToViewTableMapping, viewEC, true, otherCompensationPred);
        if (otherCompensationPred == null) {
            // Skip it
            return null;
        }
    }
    final RexNode queryCompensationPred = RexUtil.not(RexUtil.composeConjunction(rexBuilder,
            ImmutableList.of(compensationColumnsEquiPred, otherCompensationPred)));

    // Generate query rewriting.
    RelNode rewrittenPlan = relBuilder.push(target)
            .filter(simplify.simplifyUnknownAsFalse(queryCompensationPred)).build();
    if (unionRewritingPullProgram != null) {
        return aggregate.copy(aggregate.getTraitSet(), ImmutableList
                .of(newAggregateInput.copy(newAggregateInput.getTraitSet(), ImmutableList.of(rewrittenPlan))));
    }
    return aggregate.copy(aggregate.getTraitSet(), ImmutableList.of(rewrittenPlan));
}
 

/**
 * Reduces all calls to AVG, STDDEV_POP, STDDEV_SAMP, VAR_POP, VAR_SAMP in
 * the aggregates list to.
 *
 * <p>It handles newly generated common subexpressions since this was done
 * at the sql2rel stage.
 */
private void reduceAggs(
    RelOptRuleCall ruleCall,
    Aggregate oldAggRel) {
  RexBuilder rexBuilder = oldAggRel.getCluster().getRexBuilder();

  List<AggregateCall> oldCalls = oldAggRel.getAggCallList();
  final int nGroups = oldAggRel.getGroupCount();

  List<AggregateCall> newCalls = new ArrayList<>();
  Map<AggregateCall, RexNode> aggCallMapping =
      new HashMap<>();

  List<RexNode> projList = new ArrayList<>();

  // pass through group key
  for (int i = 0; i < nGroups; ++i) {
    projList.add(
        rexBuilder.makeInputRef(
            getFieldType(oldAggRel, i),
            i));
  }

  // List of input expressions. If a particular aggregate needs more, it
  // will add an expression to the end, and we will create an extra
  // project.
  RelNode input = oldAggRel.getInput();
  List<RexNode> inputExprs = new ArrayList<>();
  for (RelDataTypeField field : input.getRowType().getFieldList()) {
    inputExprs.add(
        rexBuilder.makeInputRef(
            field.getType(), inputExprs.size()));
  }

  // create new agg function calls and rest of project list together
  for (AggregateCall oldCall : oldCalls) {
    projList.add(
        reduceAgg(
            oldAggRel, oldCall, newCalls, aggCallMapping, inputExprs));
  }

  final int extraArgCount =
      inputExprs.size() - input.getRowType().getFieldCount();
  if (extraArgCount > 0) {
    input =
        relBuilderFactory
            .create(input.getCluster(), null)
            .push(input)
            .projectNamed(
                inputExprs,
                CompositeList.of(
                input.getRowType().getFieldNames(),
                Collections.nCopies(
                    extraArgCount,
                    null)),
                true)
            .build();
  }
  Aggregate newAggRel =
      newAggregateRel(
          oldAggRel, input, newCalls);

  RelNode projectRel =
      relBuilderFactory
          .create(newAggRel.getCluster(), null)
          .push(newAggRel)
          .projectNamed(projList, oldAggRel.getRowType().getFieldNames(), true)
          .build();

  ruleCall.transformTo(projectRel);
}
 

@Override protected RelNode rewriteQuery(
    RelBuilder relBuilder,
    RexBuilder rexBuilder,
    RexSimplify simplify,
    RelMetadataQuery mq,
    RexNode compensationColumnsEquiPred,
    RexNode otherCompensationPred,
    Project topProject,
    RelNode node,
    BiMap<RelTableRef, RelTableRef> queryToViewTableMapping,
    EquivalenceClasses viewEC, EquivalenceClasses queryEC) {
  Aggregate aggregate = (Aggregate) node;

  // Our target node is the node below the root, which should have the maximum
  // number of available expressions in the tree in order to maximize our
  // number of rewritings.
  // If the program is available, we execute it to maximize rewriting opportunities.
  // For instance, a program might pull up all the expressions that are below the
  // aggregate so we can introduce compensation filters easily. This is important
  // depending on the planner strategy.
  RelNode newAggregateInput = aggregate.getInput(0);
  RelNode target = aggregate.getInput(0);
  if (unionRewritingPullProgram != null) {
    final HepPlanner tmpPlanner = new HepPlanner(unionRewritingPullProgram);
    tmpPlanner.setRoot(newAggregateInput);
    newAggregateInput = tmpPlanner.findBestExp();
    target = newAggregateInput.getInput(0);
  }

  // We need to check that all columns required by compensating predicates
  // are contained in the query.
  List<RexNode> queryExprs = extractReferences(rexBuilder, target);
  if (!compensationColumnsEquiPred.isAlwaysTrue()) {
    compensationColumnsEquiPred = rewriteExpression(rexBuilder, mq,
        target, target, queryExprs, queryToViewTableMapping, queryEC, false,
        compensationColumnsEquiPred);
    if (compensationColumnsEquiPred == null) {
      // Skip it
      return null;
    }
  }
  // For the rest, we use the query equivalence classes
  if (!otherCompensationPred.isAlwaysTrue()) {
    otherCompensationPred = rewriteExpression(rexBuilder, mq,
        target, target, queryExprs, queryToViewTableMapping, viewEC, true,
        otherCompensationPred);
    if (otherCompensationPred == null) {
      // Skip it
      return null;
    }
  }
  final RexNode queryCompensationPred = RexUtil.not(
      RexUtil.composeConjunction(rexBuilder,
          ImmutableList.of(compensationColumnsEquiPred,
              otherCompensationPred)));

  // Generate query rewriting.
  RelNode rewrittenPlan = relBuilder
      .push(target)
      .filter(simplify.simplifyUnknownAsFalse(queryCompensationPred))
      .build();
  if (unionRewritingPullProgram != null) {
    return aggregate.copy(aggregate.getTraitSet(),
        ImmutableList.of(
            newAggregateInput.copy(newAggregateInput.getTraitSet(),
                ImmutableList.of(rewrittenPlan))));
  }
  return aggregate.copy(aggregate.getTraitSet(), ImmutableList.of(rewrittenPlan));
}
 

public void onMatch(RelOptRuleCall call) {
  final Aggregate aggregate = call.rel(0);
  final RelNode input = aggregate.getInput();
  final RelMetadataQuery mq = call.getMetadataQuery();
  if (!SqlFunctions.isTrue(mq.areColumnsUnique(input, aggregate.getGroupSet()))) {
    return;
  }

  final RelBuilder relBuilder = call.builder();
  final RexBuilder rexBuilder = relBuilder.getRexBuilder();
  final List<RexNode> projects = new ArrayList<>();
  for (AggregateCall aggCall : aggregate.getAggCallList()) {
    final SqlAggFunction aggregation = aggCall.getAggregation();
    if (aggregation.getKind() == SqlKind.SUM0) {
      // Bail out for SUM0 to avoid potential infinite rule matching,
      // because it may be generated by transforming SUM aggregate
      // function to SUM0 and COUNT.
      return;
    }
    final SqlSplittableAggFunction splitter =
        Objects.requireNonNull(
            aggregation.unwrap(SqlSplittableAggFunction.class));
    final RexNode singleton = splitter.singleton(
        rexBuilder, input.getRowType(), aggCall);
    projects.add(singleton);
  }

  final RelNode newInput = convert(input, aggregate.getTraitSet().simplify());
  relBuilder.push(newInput);
  if (!projects.isEmpty()) {
    projects.addAll(0, relBuilder.fields(aggregate.getGroupSet()));
    relBuilder.project(projects);
  } else if (newInput.getRowType().getFieldCount()
      > aggregate.getRowType().getFieldCount()) {
    // If aggregate was projecting a subset of columns, and there were no
    // aggregate functions, add a project for the same effect.
    relBuilder.project(relBuilder.fields(aggregate.getGroupSet()));
  }
  call.getPlanner().prune(aggregate);
  call.transformTo(relBuilder.build());
}