Example #1
0
 /**
  * Creates a relational expression which permutes the output fields of a relational expression
  * according to a permutation.
  *
  * <p>Optimizations:
  *
  * <ul>
  *   <li>If the relational expression is a {@link CalcRel} or {@link ProjectRel} which is already
  *       acting as a permutation, combines the new permutation with the old;
  *   <li>If the permutation is the identity, returns the original relational expression.
  * </ul>
  *
  * <p>If a permutation is combined with its inverse, these optimizations would combine to remove
  * them both.
  *
  * @param rel Relational expression
  * @param permutation Permutation to apply to fields
  * @param fieldNames Field names; if null, or if a particular entry is null, the name of the
  *     permuted field is used
  * @return relational expression which permutes its input fields
  */
 public static RelNode permute(RelNode rel, Permutation permutation, List<String> fieldNames) {
   if (permutation.isIdentity()) {
     return rel;
   }
   if (rel instanceof CalcRel) {
     CalcRel calcRel = (CalcRel) rel;
     Permutation permutation1 = calcRel.getProgram().getPermutation();
     if (permutation1 != null) {
       Permutation permutation2 = permutation.product(permutation1);
       return permute(rel, permutation2, null);
     }
   }
   if (rel instanceof ProjectRel) {
     Permutation permutation1 = ((ProjectRel) rel).getPermutation();
     if (permutation1 != null) {
       Permutation permutation2 = permutation.product(permutation1);
       return permute(rel, permutation2, null);
     }
   }
   final List<RelDataType> outputTypeList = new ArrayList<RelDataType>();
   final List<String> outputNameList = new ArrayList<String>();
   final List<RexNode> exprList = new ArrayList<RexNode>();
   final List<RexLocalRef> projectRefList = new ArrayList<RexLocalRef>();
   final List<RelDataTypeField> fields = rel.getRowType().getFieldList();
   for (int i = 0; i < permutation.getTargetCount(); i++) {
     int target = permutation.getTarget(i);
     final RelDataTypeField targetField = fields.get(target);
     outputTypeList.add(targetField.getType());
     outputNameList.add(
         ((fieldNames == null) || (fieldNames.size() <= i) || (fieldNames.get(i) == null))
             ? targetField.getName()
             : fieldNames.get(i));
     exprList.add(rel.getCluster().getRexBuilder().makeInputRef(fields.get(i).getType(), i));
     final int source = permutation.getSource(i);
     projectRefList.add(new RexLocalRef(source, fields.get(source).getType()));
   }
   final RexProgram program =
       new RexProgram(
           rel.getRowType(),
           exprList,
           projectRefList,
           null,
           rel.getCluster().getTypeFactory().createStructType(outputTypeList, outputNameList));
   return new CalcRel(
       rel.getCluster(),
       rel.getTraitSet(),
       rel,
       program.getOutputRowType(),
       program,
       Collections.<RelCollation>emptyList());
 }
Example #2
0
 /**
  * Creates a relational expression which projects an array of expressions, and optionally
  * optimizes.
  *
  * <p>The result may not be a {@link ProjectRel}. If the projection is trivial, <code>child</code>
  * is returned directly; and future versions may return other formulations of expressions, such as
  * {@link CalcRel}.
  *
  * @param child input relational expression
  * @param exprs list of expressions for the input columns
  * @param fieldNames aliases of the expressions, or null to generate
  * @param optimize Whether to return <code>child</code> unchanged if the projections are trivial.
  */
 public static RelNode createProject(
     RelNode child, List<RexNode> exprs, List<String> fieldNames, boolean optimize) {
   final RelOptCluster cluster = child.getCluster();
   final RexProgram program =
       RexProgram.create(child.getRowType(), exprs, null, fieldNames, cluster.getRexBuilder());
   final List<RelCollation> collationList = program.getCollations(child.getCollationList());
   if (DeprecateProjectAndFilter) {
     return new CalcRel(
         cluster, child.getTraitSet(), child, program.getOutputRowType(), program, collationList);
   } else {
     final RelDataType rowType =
         RexUtil.createStructType(cluster.getTypeFactory(), exprs, fieldNames);
     if (optimize && RemoveTrivialProjectRule.isIdentity(exprs, rowType, child.getRowType())) {
       return child;
     }
     return new ProjectRel(
         cluster,
         cluster.traitSetOf(
             collationList.isEmpty() ? RelCollationImpl.EMPTY : collationList.get(0)),
         child,
         exprs,
         rowType,
         ProjectRelBase.Flags.Boxed);
   }
 }
Example #3
0
 /**
  * Creates a relational expression which projects an array of expressions, and optionally
  * optimizes.
  *
  * <p>The result may not be a {@link ProjectRel}. If the projection is trivial, <code>child</code>
  * is returned directly; and future versions may return other formulations of expressions, such as
  * {@link CalcRel}.
  *
  * @param child input relational expression
  * @param exprs list of expressions for the input columns
  * @param fieldNames aliases of the expressions, or null to generate
  * @param optimize Whether to return <code>child</code> unchanged if the projections are trivial.
  */
 public static RelNode createProject(
     RelNode child, List<RexNode> exprs, List<String> fieldNames, boolean optimize) {
   final RelOptCluster cluster = child.getCluster();
   final RexProgram program =
       RexProgram.create(child.getRowType(), exprs, null, fieldNames, cluster.getRexBuilder());
   final List<RelCollation> collationList = program.getCollations(child.getCollationList());
   if (DEPRECATE_PROJECT_AND_FILTER) {
     return new CalcRel(
         cluster, child.getTraitSet(), child, program.getOutputRowType(), program, collationList);
   } else {
     final RelDataType rowType =
         RexUtil.createStructType(
             cluster.getTypeFactory(),
             exprs,
             fieldNames == null
                 ? null
                 : SqlValidatorUtil.uniquify(fieldNames, SqlValidatorUtil.F_SUGGESTER));
     if (optimize && RemoveTrivialProjectRule.isIdentity(exprs, rowType, child.getRowType())) {
       return child;
     }
     return new ProjectRel(
         cluster,
         cluster.traitSetOf(
             collationList.isEmpty() ? RelCollationImpl.EMPTY : collationList.get(0)),
         child,
         exprs,
         rowType,
         ProjectRelBase.Flags.BOXED);
   }
 }
Example #4
0
 /**
  * Creates a relational expression which filters according to a given condition, returning the
  * same fields as its input.
  *
  * @param child Child relational expression
  * @param condition Condition
  * @return Relational expression
  */
 public static RelNode createFilter(RelNode child, RexNode condition) {
   if (DeprecateProjectAndFilter) {
     final RelOptCluster cluster = child.getCluster();
     RexProgramBuilder builder =
         new RexProgramBuilder(child.getRowType(), cluster.getRexBuilder());
     builder.addIdentity();
     builder.addCondition(condition);
     final RexProgram program = builder.getProgram();
     return new CalcRel(
         cluster,
         child.getTraitSet(),
         child,
         program.getOutputRowType(),
         program,
         Collections.<RelCollation>emptyList());
   } else {
     return new FilterRel(child.getCluster(), child, condition);
   }
 }
Example #5
0
 /**
  * Creates a relational expression which projects the output fields of a relational expression
  * according to a partial mapping.
  *
  * <p>A partial mapping is weaker than a permutation: every target has one source, but a source
  * may have 0, 1 or more than one targets. Usually the result will have fewer fields than the
  * source, unless some source fields are projected multiple times.
  *
  * <p>This method could optimize the result as {@link #permute} does, but does not at present.
  *
  * @param rel Relational expression
  * @param mapping Mapping from source fields to target fields. The mapping type must obey the
  *     constaints {@link MappingType#isMandatorySource()} and {@link
  *     MappingType#isSingleSource()}, as does {@link MappingType#InverseFunction}.
  * @param fieldNames Field names; if null, or if a particular entry is null, the name of the
  *     permuted field is used
  * @return relational expression which projects a subset of the input fields
  */
 public static RelNode projectMapping(RelNode rel, Mapping mapping, List<String> fieldNames) {
   assert mapping.getMappingType().isSingleSource();
   assert mapping.getMappingType().isMandatorySource();
   if (mapping.isIdentity()) {
     return rel;
   }
   final List<RelDataType> outputTypeList = new ArrayList<RelDataType>();
   final List<String> outputNameList = new ArrayList<String>();
   final List<RexNode> exprList = new ArrayList<RexNode>();
   final List<RexLocalRef> projectRefList = new ArrayList<RexLocalRef>();
   final List<RelDataTypeField> fields = rel.getRowType().getFieldList();
   for (int i = 0; i < fields.size(); i++) {
     final RelDataTypeField field = fields.get(i);
     exprList.add(rel.getCluster().getRexBuilder().makeInputRef(field.getType(), i));
   }
   for (int i = 0; i < mapping.getTargetCount(); i++) {
     int source = mapping.getSource(i);
     final RelDataTypeField sourceField = fields.get(source);
     outputTypeList.add(sourceField.getType());
     outputNameList.add(
         ((fieldNames == null) || (fieldNames.size() <= i) || (fieldNames.get(i) == null))
             ? sourceField.getName()
             : fieldNames.get(i));
     projectRefList.add(new RexLocalRef(source, sourceField.getType()));
   }
   final RexProgram program =
       new RexProgram(
           rel.getRowType(),
           exprList,
           projectRefList,
           null,
           rel.getCluster().getTypeFactory().createStructType(outputTypeList, outputNameList));
   return new CalcRel(
       rel.getCluster(),
       rel.getTraitSet(),
       rel,
       program.getOutputRowType(),
       program,
       Collections.<RelCollation>emptyList());
 }
Example #6
0
 /**
  * Trims a child relational expression, then adds back a dummy project to restore the fields that
  * were removed.
  *
  * <p>Sounds pointless? It causes unused fields to be removed further down the tree (towards the
  * leaves), but it ensure that the consuming relational expression continues to see the same
  * fields.
  *
  * @param rel Relational expression
  * @param input Input relational expression, whose fields to trim
  * @param fieldsUsed Bitmap of fields needed by the consumer
  * @return New relational expression and its field mapping
  */
 protected TrimResult trimChildRestore(
     RelNode rel, RelNode input, BitSet fieldsUsed, Set<RelDataTypeField> extraFields) {
   TrimResult trimResult = trimChild(rel, input, fieldsUsed, extraFields);
   if (trimResult.right.isIdentity()) {
     return trimResult;
   }
   final RelDataType rowType = input.getRowType();
   List<RelDataTypeField> fieldList = rowType.getFieldList();
   final List<RexNode> exprList = new ArrayList<RexNode>();
   final List<String> nameList = rowType.getFieldNames();
   RexBuilder rexBuilder = rel.getCluster().getRexBuilder();
   assert trimResult.right.getSourceCount() == fieldList.size();
   for (int i = 0; i < fieldList.size(); i++) {
     int source = trimResult.right.getTargetOpt(i);
     RelDataTypeField field = fieldList.get(i);
     exprList.add(
         source < 0
             ? rexBuilder.makeZeroLiteral(field.getType())
             : rexBuilder.makeInputRef(field.getType(), source));
   }
   RelNode project = CalcRel.createProject(trimResult.left, exprList, nameList);
   return new TrimResult(project, Mappings.createIdentity(fieldList.size()));
 }
  /**
   * Creates new RelNodes replacing/removing the original project/row scan
   *
   * @param projectedScan new scan that is now projected
   * @param origProject original projection
   * @param needRename true if fields from the row scan need to be renamed
   * @param newProject projection that contains the new projection expressions, in the case where
   *     the original projection cannot be removed because it projects expressions
   * @return new RelNode
   */
  public RelNode createNewRelNode(
      RelNode projectedScan, ProjectRel origProject, boolean needRename, ProjectRel newProject) {
    RelNode scanRel;
    if (needRename) {
      // Replace calling convention with FENNEL_EXEC_CONVENTION
      RelTraitSet traits = RelOptUtil.clone(origProject.getTraits());
      traits.setTrait(CallingConventionTraitDef.instance, FennelRel.FENNEL_EXEC_CONVENTION);
      if (!traits.equals(projectedScan.getTraits())) {
        RelNode mergedProjectedScan = convert(projectedScan, traits);
        RelOptPlanner planner = projectedScan.getCluster().getPlanner();
        // register projectedScan == mergedProjectedScan
        // so mergedProjectedScan will have a set later on
        projectedScan = planner.ensureRegistered(mergedProjectedScan, projectedScan);
      }
      scanRel =
          new FennelRenameRel(
              origProject.getCluster(),
              projectedScan,
              RelOptUtil.getFieldNames(origProject.getRowType()),
              traits);
    } else {
      scanRel = projectedScan;
    }

    if (newProject == null) {
      return scanRel;
    } else {
      // in the case where the projection had expressions, put the
      // new, modified projection on top of the projected row scan
      return (ProjectRel)
          CalcRel.createProject(
              scanRel,
              newProject.getProjectExps(),
              RelOptUtil.getFieldNames(newProject.getRowType()));
    }
  }
 static FarragoSession getSession(RelNode rel) {
   FarragoSessionPlanner planner = (FarragoSessionPlanner) rel.getCluster().getPlanner();
   FarragoSessionPreparingStmt preparingStmt = planner.getPreparingStmt();
   return preparingStmt.getSession();
 }
  /**
   * Reduces a list of expressions.
   *
   * @param rel Relational expression
   * @param expList List of expressions, modified in place
   * @return whether reduction found something to change, and succeeded
   */
  static boolean reduceExpressions(RelNode rel, List<RexNode> expList) {
    RexBuilder rexBuilder = rel.getCluster().getRexBuilder();

    // Find reducible expressions.
    FarragoSessionPlanner planner = (FarragoSessionPlanner) rel.getCluster().getPlanner();
    FarragoSessionPreparingStmt preparingStmt = planner.getPreparingStmt();
    List<RexNode> constExps = new ArrayList<RexNode>();
    List<Boolean> addCasts = new ArrayList<Boolean>();
    List<RexNode> removableCasts = new ArrayList<RexNode>();
    findReducibleExps(preparingStmt, expList, constExps, addCasts, removableCasts);
    if (constExps.isEmpty() && removableCasts.isEmpty()) {
      return false;
    }

    // Remove redundant casts before reducing constant expressions.
    // If the argument to the redundant cast is a reducible constant,
    // reducing that argument to a constant first will result in not being
    // able to locate the original cast expression.
    if (!removableCasts.isEmpty()) {
      List<RexNode> reducedExprs = new ArrayList<RexNode>();
      List<Boolean> noCasts = new ArrayList<Boolean>();
      for (RexNode exp : removableCasts) {
        RexCall call = (RexCall) exp;
        reducedExprs.add(call.getOperands()[0]);
        noCasts.add(false);
      }
      RexReplacer replacer = new RexReplacer(rexBuilder, removableCasts, reducedExprs, noCasts);
      replacer.apply(expList);
    }

    if (constExps.isEmpty()) {
      return true;
    }

    // Compute the values they reduce to.
    List<RexNode> reducedValues = new ArrayList<RexNode>();
    ReentrantValuesStmt reentrantStmt =
        new ReentrantValuesStmt(
            preparingStmt.getRootStmtContext(), rexBuilder, constExps, reducedValues);
    FarragoSession session = getSession(rel);
    reentrantStmt.execute(session, true);
    if (reentrantStmt.failed) {
      return false;
    }

    // For ProjectRel, we have to be sure to preserve the result
    // types, so always cast regardless of the expression type.
    // For other RelNodes like FilterRel, in general, this isn't necessary,
    // and the presence of casts could hinder other rules such as sarg
    // analysis, which require bare literals.  But there are special cases,
    // like when the expression is a UDR argument, that need to be
    // handled as special cases.
    if (rel instanceof ProjectRel) {
      for (int i = 0; i < reducedValues.size(); i++) {
        addCasts.set(i, true);
      }
    }

    RexReplacer replacer = new RexReplacer(rexBuilder, constExps, reducedValues, addCasts);
    replacer.apply(expList);
    return true;
  }