Пример #1
0
  /** @return true if all tuples match rowType; otherwise, assert on mismatch */
  private boolean assertRowType() {
    for (List<RexLiteral> tuple : tuples) {
      assert tuple.size() == rowType.getFieldCount();
      for (Pair<RexLiteral, RelDataTypeField> pair : Pair.zip(tuple, rowType.getFieldList())) {
        RexLiteral literal = pair.left;
        RelDataType fieldType = pair.right.getType();

        // TODO jvs 19-Feb-2006: strengthen this a bit.  For example,
        // overflow, rounding, and padding/truncation must already have
        // been dealt with.
        if (!RexLiteral.isNullLiteral(literal)) {
          assert (SqlTypeUtil.canAssignFrom(fieldType, literal.getType()));
        }
      }
    }
    return true;
  }
Пример #2
0
 // implement RelNode
 public void explain(RelOptPlanWriter pw) {
   // A little adapter just to get the tuples to come out
   // with curly brackets instead of square brackets.  Plus
   // more whitespace for readability.
   List<String> renderList = new ArrayList<String>();
   for (List<RexLiteral> tuple : tuples) {
     String s = tuple.toString();
     assert (s.startsWith("["));
     assert (s.endsWith("]"));
     renderList.add("{ " + s.substring(1, s.length() - 1) + " }");
   }
   if (pw.getDetailLevel() == SqlExplainLevel.DIGEST_ATTRIBUTES) {
     // For rel digest, include the row type since a rendered
     // literal may leave the type ambiguous (e.g. "null").
     pw.explain(this, new String[] {"type", "tuples"}, new Object[] {rowType, renderList});
   } else {
     // For normal EXPLAIN PLAN, omit the type.
     pw.explain(this, new String[] {"tuples"}, new Object[] {renderList});
   }
 }
 private List<AggregateCall> transformAggCalls(
     RelDataTypeFactory typeFactory, int nGroupCols, List<AggregateCall> origCalls) {
   List<AggregateCall> newCalls = new ArrayList<AggregateCall>();
   int iInput = nGroupCols;
   for (AggregateCall origCall : origCalls) {
     if (origCall.isDistinct()
         || !SUPPORTED_AGGREGATES.containsKey(origCall.getAggregation().getClass())) {
       return null;
     }
     Aggregation aggFun;
     RelDataType aggType;
     if (origCall.getAggregation().getName().equals("COUNT")) {
       aggFun = new SqlSumEmptyIsZeroAggFunction(origCall.getType());
       SqlAggFunction af = (SqlAggFunction) aggFun;
       final AggregateRelBase.AggCallBinding binding =
           new AggregateRelBase.AggCallBinding(
               typeFactory, af, Collections.singletonList(origCall.getType()), nGroupCols);
       // count(any) is always not null, however nullability of sum might
       // depend on the number of columns in GROUP BY.
       // Here we use SUM0 since we are sure we will not face nullable
       // inputs nor we'll face empty set.
       aggType = af.inferReturnType(binding);
     } else {
       aggFun = origCall.getAggregation();
       aggType = origCall.getType();
     }
     AggregateCall newCall =
         new AggregateCall(
             aggFun,
             origCall.isDistinct(),
             Collections.singletonList(iInput),
             aggType,
             origCall.getName());
     newCalls.add(newCall);
     ++iInput;
   }
   return newCalls;
 }
  public void onMatch(RelOptRuleCall call) {
    AggregateRel aggRel = call.rel(0);
    UnionRel unionRel = call.rel(1);

    if (!unionRel.all) {
      // This transformation is only valid for UNION ALL.
      // Consider t1(i) with rows (5), (5) and t2(i) with
      // rows (5), (10), and the query
      // select sum(i) from (select i from t1) union (select i from t2).
      // The correct answer is 15.  If we apply the transformation,
      // we get
      // select sum(i) from
      // (select sum(i) as i from t1) union (select sum(i) as i from t2)
      // which yields 25 (incorrect).
      return;
    }

    RelOptCluster cluster = unionRel.getCluster();

    List<AggregateCall> transformedAggCalls =
        transformAggCalls(
            aggRel.getCluster().getTypeFactory(),
            aggRel.getGroupSet().cardinality(),
            aggRel.getAggCallList());
    if (transformedAggCalls == null) {
      // we've detected the presence of something like AVG,
      // which we can't handle
      return;
    }

    boolean anyTransformed = false;

    // create corresponding aggs on top of each union child
    List<RelNode> newUnionInputs = new ArrayList<RelNode>();
    for (RelNode input : unionRel.getInputs()) {
      boolean alreadyUnique = RelMdUtil.areColumnsDefinitelyUnique(input, aggRel.getGroupSet());

      if (alreadyUnique) {
        newUnionInputs.add(input);
      } else {
        anyTransformed = true;
        newUnionInputs.add(
            new AggregateRel(cluster, input, aggRel.getGroupSet(), aggRel.getAggCallList()));
      }
    }

    if (!anyTransformed) {
      // none of the children could benefit from the pushdown,
      // so bail out (preventing the infinite loop to which most
      // planners would succumb)
      return;
    }

    // create a new union whose children are the aggs created above
    UnionRel newUnionRel = new UnionRel(cluster, newUnionInputs, true);

    AggregateRel newTopAggRel =
        new AggregateRel(cluster, newUnionRel, aggRel.getGroupSet(), transformedAggCalls);

    // In case we transformed any COUNT (which is always NOT NULL)
    // to SUM (which is always NULLABLE), cast back to keep the
    // planner happy.
    RelNode castRel = RelOptUtil.createCastRel(newTopAggRel, aggRel.getRowType(), false);

    call.transformTo(castRel);
  }