Examples with RexTableInputRef org.apache.calcite.rex.RexTableInputRef used on opensource projects

Example 1 with RexTableInputRef

use of org.apache.calcite.rex.RexTableInputRef in project calcite by apache.

the class AbstractMaterializedViewRule method generateEquivalenceClasses.

/**
 * Given the equi-column predicates of the source and the target and the
 * computed equivalence classes, it extracts possible mappings between
 * the equivalence classes.
 *
 * <p>If there is no mapping, it returns null. If there is a exact match,
 * it will return a compensation predicate that evaluates to true.
 * Finally, if a compensation predicate needs to be enforced on top of
 * the target to make the equivalences classes match, it returns that
 * compensation predicate.
 */
private static RexNode generateEquivalenceClasses(RexBuilder rexBuilder, EquivalenceClasses sourceEC, EquivalenceClasses targetEC) {
    if (sourceEC.getEquivalenceClasses().isEmpty() && targetEC.getEquivalenceClasses().isEmpty()) {
        // Empty mapping and compensation predicate
        return rexBuilder.makeLiteral(true);
    }
    if (sourceEC.getEquivalenceClasses().isEmpty() && !targetEC.getEquivalenceClasses().isEmpty()) {
        // No column equality predicates in source, but column equality predicates in target
        return null;
    }
    final List<Set<RexTableInputRef>> sourceEquivalenceClasses = sourceEC.getEquivalenceClasses();
    final List<Set<RexTableInputRef>> targetEquivalenceClasses = targetEC.getEquivalenceClasses();
    final Multimap<Integer, Integer> mapping = extractPossibleMapping(sourceEquivalenceClasses, targetEquivalenceClasses);
    if (mapping == null) {
        // bail out
        return null;
    }
    // Create the compensation predicate
    RexNode compensationPredicate = rexBuilder.makeLiteral(true);
    for (int i = 0; i < sourceEquivalenceClasses.size(); i++) {
        if (!mapping.containsKey(i)) {
            // Add all predicates
            Iterator<RexTableInputRef> it = sourceEquivalenceClasses.get(i).iterator();
            RexTableInputRef e0 = it.next();
            while (it.hasNext()) {
                RexNode equals = rexBuilder.makeCall(SqlStdOperatorTable.EQUALS, e0, it.next());
                compensationPredicate = rexBuilder.makeCall(SqlStdOperatorTable.AND, compensationPredicate, equals);
            }
        } else {
            // Add only predicates that are not there
            for (int j : mapping.get(i)) {
                Set<RexTableInputRef> difference = new HashSet<>(sourceEquivalenceClasses.get(i));
                difference.removeAll(targetEquivalenceClasses.get(j));
                for (RexTableInputRef e : difference) {
                    RexNode equals = rexBuilder.makeCall(SqlStdOperatorTable.EQUALS, e, targetEquivalenceClasses.get(j).iterator().next());
                    compensationPredicate = rexBuilder.makeCall(SqlStdOperatorTable.AND, compensationPredicate, equals);
                }
            }
        }
    }
    return compensationPredicate;
}

Example 2 with RexTableInputRef

use of org.apache.calcite.rex.RexTableInputRef in project calcite by apache.

the class AbstractMaterializedViewRule method replaceWithOriginalReferences.

/**
 * Given the input expression, it will replace (sub)expressions when possible
 * using the content of the mapping. In particular, the mapping contains the
 * digest of the expression and the index that the replacement input ref should
 * point to.
 */
private static RexNode replaceWithOriginalReferences(final RexBuilder rexBuilder, final RelNode node, final NodeLineage nodeLineage, final RexNode exprToRewrite) {
    // Currently we allow the following:
    // 1) compensation pred can be directly map to expression
    // 2) all references in compensation pred can be map to expressions
    // We support bypassing lossless casts.
    RexShuttle visitor = new RexShuttle() {

        @Override
        public RexNode visitCall(RexCall call) {
            RexNode rw = replace(call);
            return rw != null ? rw : super.visitCall(call);
        }

        @Override
        public RexNode visitTableInputRef(RexTableInputRef inputRef) {
            RexNode rw = replace(inputRef);
            return rw != null ? rw : super.visitTableInputRef(inputRef);
        }

        private RexNode replace(RexNode e) {
            Integer pos = nodeLineage.exprsLineage.get(e.toString());
            if (pos != null) {
                // Found it
                return rexBuilder.makeInputRef(node, pos);
            }
            pos = nodeLineage.exprsLineageLosslessCasts.get(e.toString());
            if (pos != null) {
                // Found it
                return rexBuilder.makeCast(e.getType(), rexBuilder.makeInputRef(node, pos));
            }
            return null;
        }
    };
    return visitor.apply(exprToRewrite);
}

Example 3 with RexTableInputRef

use of org.apache.calcite.rex.RexTableInputRef in project calcite by apache.

the class AbstractMaterializedViewRule method perform.

/**
 * Rewriting logic is based on "Optimizing Queries Using Materialized Views:
 * A Practical, Scalable Solution" by Goldstein and Larson.
 *
 * <p>On the query side, rules matches a Project-node chain or node, where node
 * is either an Aggregate or a Join. Subplan rooted at the node operator must
 * be composed of one or more of the following operators: TableScan, Project,
 * Filter, and Join.
 *
 * <p>For each join MV, we need to check the following:
 * <ol>
 * <li> The plan rooted at the Join operator in the view produces all rows
 * needed by the plan rooted at the Join operator in the query.</li>
 * <li> All columns required by compensating predicates, i.e., predicates that
 * need to be enforced over the view, are available at the view output.</li>
 * <li> All output expressions can be computed from the output of the view.</li>
 * <li> All output rows occur with the correct duplication factor. We might
 * rely on existing Unique-Key - Foreign-Key relationships to extract that
 * information.</li>
 * </ol>
 *
 * <p>In turn, for each aggregate MV, we need to check the following:
 * <ol>
 * <li> The plan rooted at the Aggregate operator in the view produces all rows
 * needed by the plan rooted at the Aggregate operator in the query.</li>
 * <li> All columns required by compensating predicates, i.e., predicates that
 * need to be enforced over the view, are available at the view output.</li>
 * <li> The grouping columns in the query are a subset of the grouping columns
 * in the view.</li>
 * <li> All columns required to perform further grouping are available in the
 * view output.</li>
 * <li> All columns required to compute output expressions are available in the
 * view output.</li>
 * </ol>
 *
 * <p>The rule contains multiple extensions compared to the original paper. One of
 * them is the possibility of creating rewritings using Union operators, e.g., if
 * the result of a query is partially contained in the materialized view.
 */
protected void perform(RelOptRuleCall call, Project topProject, RelNode node) {
    final RexBuilder rexBuilder = node.getCluster().getRexBuilder();
    final RelMetadataQuery mq = RelMetadataQuery.instance();
    final RelOptPlanner planner = call.getPlanner();
    final RexExecutor executor = Util.first(planner.getExecutor(), RexUtil.EXECUTOR);
    final RelOptPredicateList predicates = RelOptPredicateList.EMPTY;
    final RexSimplify simplify = new RexSimplify(rexBuilder, predicates, true, executor);
    final List<RelOptMaterialization> materializations = (planner instanceof VolcanoPlanner) ? ((VolcanoPlanner) planner).getMaterializations() : ImmutableList.<RelOptMaterialization>of();
    if (!materializations.isEmpty()) {
        // try to generate a rewriting are met
        if (!isValidPlan(topProject, node, mq)) {
            return;
        }
        // Obtain applicable (filtered) materializations
        // TODO: Filtering of relevant materializations needs to be
        // improved so we gather only materializations that might
        // actually generate a valid rewriting.
        final List<RelOptMaterialization> applicableMaterializations = RelOptMaterializations.getApplicableMaterializations(node, materializations);
        if (!applicableMaterializations.isEmpty()) {
            // 2. Initialize all query related auxiliary data structures
            // that will be used throughout query rewriting process
            // Generate query table references
            final Set<RelTableRef> queryTableRefs = mq.getTableReferences(node);
            if (queryTableRefs == null) {
                // Bail out
                return;
            }
            // Extract query predicates
            final RelOptPredicateList queryPredicateList = mq.getAllPredicates(node);
            if (queryPredicateList == null) {
                // Bail out
                return;
            }
            final RexNode pred = simplify.simplify(RexUtil.composeConjunction(rexBuilder, queryPredicateList.pulledUpPredicates, false));
            final Triple<RexNode, RexNode, RexNode> queryPreds = splitPredicates(rexBuilder, pred);
            // Extract query equivalence classes. An equivalence class is a set
            // of columns in the query output that are known to be equal.
            final EquivalenceClasses qEC = new EquivalenceClasses();
            for (RexNode conj : RelOptUtil.conjunctions(queryPreds.getLeft())) {
                assert conj.isA(SqlKind.EQUALS);
                RexCall equiCond = (RexCall) conj;
                qEC.addEquivalenceClass((RexTableInputRef) equiCond.getOperands().get(0), (RexTableInputRef) equiCond.getOperands().get(1));
            }
            // rewrite the given query
            for (RelOptMaterialization materialization : applicableMaterializations) {
                RelNode view = materialization.tableRel;
                Project topViewProject;
                RelNode viewNode;
                if (materialization.queryRel instanceof Project) {
                    topViewProject = (Project) materialization.queryRel;
                    viewNode = topViewProject.getInput();
                } else {
                    topViewProject = null;
                    viewNode = materialization.queryRel;
                }
                // 3.1. View checks before proceeding
                if (!isValidPlan(topViewProject, viewNode, mq)) {
                    // Skip it
                    continue;
                }
                // 3.2. Initialize all query related auxiliary data structures
                // that will be used throughout query rewriting process
                // Extract view predicates
                final RelOptPredicateList viewPredicateList = mq.getAllPredicates(viewNode);
                if (viewPredicateList == null) {
                    // Skip it
                    continue;
                }
                final RexNode viewPred = simplify.simplify(RexUtil.composeConjunction(rexBuilder, viewPredicateList.pulledUpPredicates, false));
                final Triple<RexNode, RexNode, RexNode> viewPreds = splitPredicates(rexBuilder, viewPred);
                // Extract view table references
                final Set<RelTableRef> viewTableRefs = mq.getTableReferences(viewNode);
                if (viewTableRefs == null) {
                    // Bail out
                    return;
                }
                // Extract view tables
                MatchModality matchModality;
                Multimap<RexTableInputRef, RexTableInputRef> compensationEquiColumns = ArrayListMultimap.create();
                if (!queryTableRefs.equals(viewTableRefs)) {
                    // subset of query tables (add additional tables through joins if possible)
                    if (viewTableRefs.containsAll(queryTableRefs)) {
                        matchModality = MatchModality.QUERY_PARTIAL;
                        final EquivalenceClasses vEC = new EquivalenceClasses();
                        for (RexNode conj : RelOptUtil.conjunctions(viewPreds.getLeft())) {
                            assert conj.isA(SqlKind.EQUALS);
                            RexCall equiCond = (RexCall) conj;
                            vEC.addEquivalenceClass((RexTableInputRef) equiCond.getOperands().get(0), (RexTableInputRef) equiCond.getOperands().get(1));
                        }
                        if (!compensatePartial(viewTableRefs, vEC, queryTableRefs, compensationEquiColumns)) {
                            // Cannot rewrite, skip it
                            continue;
                        }
                    } else if (queryTableRefs.containsAll(viewTableRefs)) {
                        matchModality = MatchModality.VIEW_PARTIAL;
                        ViewPartialRewriting partialRewritingResult = compensateViewPartial(call.builder(), rexBuilder, mq, view, topProject, node, queryTableRefs, qEC, topViewProject, viewNode, viewTableRefs);
                        if (partialRewritingResult == null) {
                            // Cannot rewrite, skip it
                            continue;
                        }
                        // Rewrite succeeded
                        view = partialRewritingResult.newView;
                        topViewProject = partialRewritingResult.newTopViewProject;
                        viewNode = partialRewritingResult.newViewNode;
                    } else {
                        // Skip it
                        continue;
                    }
                } else {
                    matchModality = MatchModality.COMPLETE;
                }
                // 4. We map every table in the query to a table with the same qualified
                // name (all query tables are contained in the view, thus this is equivalent
                // to mapping every table in the query to a view table).
                final Multimap<RelTableRef, RelTableRef> multiMapTables = ArrayListMultimap.create();
                for (RelTableRef queryTableRef1 : queryTableRefs) {
                    for (RelTableRef queryTableRef2 : queryTableRefs) {
                        if (queryTableRef1.getQualifiedName().equals(queryTableRef2.getQualifiedName())) {
                            multiMapTables.put(queryTableRef1, queryTableRef2);
                        }
                    }
                }
                // If a table is used multiple times, we will create multiple mappings,
                // and we will try to rewrite the query using each of the mappings.
                // Then, we will try to map every source table (query) to a target
                // table (view), and if we are successful, we will try to create
                // compensation predicates to filter the view results further
                // (if needed).
                final List<BiMap<RelTableRef, RelTableRef>> flatListMappings = generateTableMappings(multiMapTables);
                for (BiMap<RelTableRef, RelTableRef> queryToViewTableMapping : flatListMappings) {
                    // TableMapping : mapping query tables -> view tables
                    // 4.0. If compensation equivalence classes exist, we need to add
                    // the mapping to the query mapping
                    final EquivalenceClasses currQEC = EquivalenceClasses.copy(qEC);
                    if (matchModality == MatchModality.QUERY_PARTIAL) {
                        for (Entry<RexTableInputRef, RexTableInputRef> e : compensationEquiColumns.entries()) {
                            // Copy origin
                            RelTableRef queryTableRef = queryToViewTableMapping.inverse().get(e.getKey().getTableRef());
                            RexTableInputRef queryColumnRef = RexTableInputRef.of(queryTableRef, e.getKey().getIndex(), e.getKey().getType());
                            // Add to query equivalence classes and table mapping
                            currQEC.addEquivalenceClass(queryColumnRef, e.getValue());
                            queryToViewTableMapping.put(e.getValue().getTableRef(), // identity
                            e.getValue().getTableRef());
                        }
                    }
                    // 4.1. Compute compensation predicates, i.e., predicates that need to be
                    // enforced over the view to retain query semantics. The resulting predicates
                    // are expressed using {@link RexTableInputRef} over the query.
                    // First, to establish relationship, we swap column references of the view
                    // predicates to point to query tables and compute equivalence classes.
                    final RexNode viewColumnsEquiPred = RexUtil.swapTableReferences(rexBuilder, viewPreds.getLeft(), queryToViewTableMapping.inverse());
                    final EquivalenceClasses queryBasedVEC = new EquivalenceClasses();
                    for (RexNode conj : RelOptUtil.conjunctions(viewColumnsEquiPred)) {
                        assert conj.isA(SqlKind.EQUALS);
                        RexCall equiCond = (RexCall) conj;
                        queryBasedVEC.addEquivalenceClass((RexTableInputRef) equiCond.getOperands().get(0), (RexTableInputRef) equiCond.getOperands().get(1));
                    }
                    Triple<RexNode, RexNode, RexNode> compensationPreds = computeCompensationPredicates(rexBuilder, simplify, currQEC, queryPreds, queryBasedVEC, viewPreds, queryToViewTableMapping);
                    if (compensationPreds == null && generateUnionRewriting) {
                        // Attempt partial rewriting using union operator. This rewriting
                        // will read some data from the view and the rest of the data from
                        // the query computation. The resulting predicates are expressed
                        // using {@link RexTableInputRef} over the view.
                        compensationPreds = computeCompensationPredicates(rexBuilder, simplify, queryBasedVEC, viewPreds, currQEC, queryPreds, queryToViewTableMapping.inverse());
                        if (compensationPreds == null) {
                            // This was our last chance to use the view, skip it
                            continue;
                        }
                        RexNode compensationColumnsEquiPred = compensationPreds.getLeft();
                        RexNode otherCompensationPred = RexUtil.composeConjunction(rexBuilder, ImmutableList.of(compensationPreds.getMiddle(), compensationPreds.getRight()), false);
                        assert !compensationColumnsEquiPred.isAlwaysTrue() || !otherCompensationPred.isAlwaysTrue();
                        // b. Generate union branch (query).
                        final RelNode unionInputQuery = rewriteQuery(call.builder(), rexBuilder, simplify, mq, compensationColumnsEquiPred, otherCompensationPred, topProject, node, queryToViewTableMapping, queryBasedVEC, currQEC);
                        if (unionInputQuery == null) {
                            // Skip it
                            continue;
                        }
                        // c. Generate union branch (view).
                        // We trigger the unifying method. This method will either create a Project
                        // or an Aggregate operator on top of the view. It will also compute the
                        // output expressions for the query.
                        final RelNode unionInputView = rewriteView(call.builder(), rexBuilder, simplify, mq, matchModality, true, view, topProject, node, topViewProject, viewNode, queryToViewTableMapping, currQEC);
                        if (unionInputView == null) {
                            // Skip it
                            continue;
                        }
                        // d. Generate final rewriting (union).
                        final RelNode result = createUnion(call.builder(), rexBuilder, topProject, unionInputQuery, unionInputView);
                        if (result == null) {
                            // Skip it
                            continue;
                        }
                        call.transformTo(result);
                    } else if (compensationPreds != null) {
                        RexNode compensationColumnsEquiPred = compensationPreds.getLeft();
                        RexNode otherCompensationPred = RexUtil.composeConjunction(rexBuilder, ImmutableList.of(compensationPreds.getMiddle(), compensationPreds.getRight()), false);
                        // a. Compute final compensation predicate.
                        if (!compensationColumnsEquiPred.isAlwaysTrue() || !otherCompensationPred.isAlwaysTrue()) {
                            // All columns required by compensating predicates must be contained
                            // in the view output (condition 2).
                            List<RexNode> viewExprs = topViewProject == null ? extractReferences(rexBuilder, view) : topViewProject.getChildExps();
                            // since we want to enforce the rest
                            if (!compensationColumnsEquiPred.isAlwaysTrue()) {
                                compensationColumnsEquiPred = rewriteExpression(rexBuilder, mq, view, viewNode, viewExprs, queryToViewTableMapping.inverse(), queryBasedVEC, false, compensationColumnsEquiPred);
                                if (compensationColumnsEquiPred == null) {
                                    // Skip it
                                    continue;
                                }
                            }
                            // For the rest, we use the query equivalence classes
                            if (!otherCompensationPred.isAlwaysTrue()) {
                                otherCompensationPred = rewriteExpression(rexBuilder, mq, view, viewNode, viewExprs, queryToViewTableMapping.inverse(), currQEC, true, otherCompensationPred);
                                if (otherCompensationPred == null) {
                                    // Skip it
                                    continue;
                                }
                            }
                        }
                        final RexNode viewCompensationPred = RexUtil.composeConjunction(rexBuilder, ImmutableList.of(compensationColumnsEquiPred, otherCompensationPred), false);
                        // b. Generate final rewriting if possible.
                        // First, we add the compensation predicate (if any) on top of the view.
                        // Then, we trigger the unifying method. This method will either create a
                        // Project or an Aggregate operator on top of the view. It will also compute
                        // the output expressions for the query.
                        RelBuilder builder = call.builder();
                        RelNode viewWithFilter;
                        if (!viewCompensationPred.isAlwaysTrue()) {
                            RexNode newPred = simplify.simplify(viewCompensationPred);
                            viewWithFilter = builder.push(view).filter(newPred).build();
                            // We add (and push) the filter to the view plan before triggering the rewriting.
                            // This is useful in case some of the columns can be folded to same value after
                            // filter is added.
                            Pair<RelNode, RelNode> pushedNodes = pushFilterToOriginalViewPlan(builder, topViewProject, viewNode, newPred);
                            topViewProject = (Project) pushedNodes.left;
                            viewNode = pushedNodes.right;
                        } else {
                            viewWithFilter = builder.push(view).build();
                        }
                        final RelNode result = rewriteView(builder, rexBuilder, simplify, mq, matchModality, false, viewWithFilter, topProject, node, topViewProject, viewNode, queryToViewTableMapping, currQEC);
                        if (result == null) {
                            // Skip it
                            continue;
                        }
                        call.transformTo(result);
                    }
                // end else
                }
            }
        }
    }
}

Example 4 with RexTableInputRef

use of org.apache.calcite.rex.RexTableInputRef in project calcite by apache.

the class AbstractMaterializedViewRule method compensatePartial.

/**
 * It checks whether the target can be rewritten using the source even though the
 * source uses additional tables. In order to do that, we need to double-check
 * that every join that exists in the source and is not in the target is a
 * cardinality-preserving join, i.e., it only appends columns to the row
 * without changing its multiplicity. Thus, the join needs to be:
 * <ul>
 * <li> Equi-join </li>
 * <li> Between all columns in the keys </li>
 * <li> Foreign-key columns do not allow NULL values </li>
 * <li> Foreign-key </li>
 * <li> Unique-key </li>
 * </ul>
 *
 * <p>If it can be rewritten, it returns true. Further, it inserts the missing equi-join
 * predicates in the input {@code compensationEquiColumns} multimap if it is provided.
 * If it cannot be rewritten, it returns false.
 */
private static boolean compensatePartial(Set<RelTableRef> sourceTableRefs, EquivalenceClasses sourceEC, Set<RelTableRef> targetTableRefs, Multimap<RexTableInputRef, RexTableInputRef> compensationEquiColumns) {
    // Create UK-FK graph with view tables
    final DirectedGraph<RelTableRef, Edge> graph = DefaultDirectedGraph.create(Edge.FACTORY);
    final Multimap<List<String>, RelTableRef> tableVNameToTableRefs = ArrayListMultimap.create();
    final Set<RelTableRef> extraTableRefs = new HashSet<>();
    for (RelTableRef tRef : sourceTableRefs) {
        // Add tables in view as vertices
        graph.addVertex(tRef);
        tableVNameToTableRefs.put(tRef.getQualifiedName(), tRef);
        if (!targetTableRefs.contains(tRef)) {
            // Add to extra tables if table is not part of the query
            extraTableRefs.add(tRef);
        }
    }
    for (RelTableRef tRef : graph.vertexSet()) {
        // Add edges between tables
        List<RelReferentialConstraint> constraints = tRef.getTable().getReferentialConstraints();
        for (RelReferentialConstraint constraint : constraints) {
            Collection<RelTableRef> parentTableRefs = tableVNameToTableRefs.get(constraint.getTargetQualifiedName());
            for (RelTableRef parentTRef : parentTableRefs) {
                boolean canBeRewritten = true;
                Multimap<RexTableInputRef, RexTableInputRef> equiColumns = ArrayListMultimap.create();
                for (int pos = 0; pos < constraint.getNumColumns(); pos++) {
                    int foreignKeyPos = constraint.getColumnPairs().get(pos).source;
                    RelDataType foreignKeyColumnType = tRef.getTable().getRowType().getFieldList().get(foreignKeyPos).getType();
                    RexTableInputRef foreignKeyColumnRef = RexTableInputRef.of(tRef, foreignKeyPos, foreignKeyColumnType);
                    int uniqueKeyPos = constraint.getColumnPairs().get(pos).target;
                    RexTableInputRef uniqueKeyColumnRef = RexTableInputRef.of(parentTRef, uniqueKeyPos, parentTRef.getTable().getRowType().getFieldList().get(uniqueKeyPos).getType());
                    if (!foreignKeyColumnType.isNullable() && sourceEC.getEquivalenceClassesMap().containsKey(uniqueKeyColumnRef) && sourceEC.getEquivalenceClassesMap().get(uniqueKeyColumnRef).contains(foreignKeyColumnRef)) {
                        equiColumns.put(foreignKeyColumnRef, uniqueKeyColumnRef);
                    } else {
                        canBeRewritten = false;
                        break;
                    }
                }
                if (canBeRewritten) {
                    // Add edge FK -> UK
                    Edge edge = graph.getEdge(tRef, parentTRef);
                    if (edge == null) {
                        edge = graph.addEdge(tRef, parentTRef);
                    }
                    edge.equiColumns.putAll(equiColumns);
                }
            }
        }
    }
    // Try to eliminate tables from graph: if we can do it, it means extra tables in
    // view are cardinality-preserving joins
    boolean done = false;
    do {
        List<RelTableRef> nodesToRemove = new ArrayList<>();
        for (RelTableRef tRef : graph.vertexSet()) {
            if (graph.getInwardEdges(tRef).size() == 1 && graph.getOutwardEdges(tRef).isEmpty()) {
                // UK-FK join
                nodesToRemove.add(tRef);
                if (compensationEquiColumns != null && extraTableRefs.contains(tRef)) {
                    // We need to add to compensation columns as the table is not present in the query
                    compensationEquiColumns.putAll(graph.getInwardEdges(tRef).get(0).equiColumns);
                }
            }
        }
        if (!nodesToRemove.isEmpty()) {
            graph.removeAllVertices(nodesToRemove);
        } else {
            done = true;
        }
    } while (!done);
    // are tables present in the query: if they are, we can try to rewrite
    if (!Collections.disjoint(graph.vertexSet(), extraTableRefs)) {
        return false;
    }
    return true;
}

Example 5 with RexTableInputRef

use of org.apache.calcite.rex.RexTableInputRef in project calcite by apache.

the class AbstractMaterializedViewRule method extractPossibleMapping.

/**
 * Given the source and target equivalence classes, it extracts the possible mappings
 * from each source equivalence class to each target equivalence class.
 *
 * <p>If any of the source equivalence classes cannot be mapped to a target equivalence
 * class, it returns null.
 */
private static Multimap<Integer, Integer> extractPossibleMapping(List<Set<RexTableInputRef>> sourceEquivalenceClasses, List<Set<RexTableInputRef>> targetEquivalenceClasses) {
    Multimap<Integer, Integer> mapping = ArrayListMultimap.create();
    for (int i = 0; i < targetEquivalenceClasses.size(); i++) {
        boolean foundQueryEquivalenceClass = false;
        final Set<RexTableInputRef> viewEquivalenceClass = targetEquivalenceClasses.get(i);
        for (int j = 0; j < sourceEquivalenceClasses.size(); j++) {
            final Set<RexTableInputRef> queryEquivalenceClass = sourceEquivalenceClasses.get(j);
            if (queryEquivalenceClass.containsAll(viewEquivalenceClass)) {
                mapping.put(j, i);
                foundQueryEquivalenceClass = true;
                break;
            }
        }
        if (!foundQueryEquivalenceClass) {
            // Target equivalence class not found in source equivalence class
            return null;
        }
    }
    return mapping;
}