/** * 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()); }
/** * 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); } }
/** * 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); } }
/** * 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); } }
/** * 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()); }
/** * 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())); } }
// Ditto for getNonCumulativeCost public RelOptCost getNonCumulativeCost(RelNode rel) { return rel.computeSelfCost(rel.getCluster().getPlanner()); }
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; }