Examples with BackendQueryHolder org.janusgraph.graphdb.query.BackendQueryHolder used on opensource projects

Example 1 with BackendQueryHolder

use of org.janusgraph.graphdb.query.BackendQueryHolder in project janusgraph by JanusGraph.

the class BasicVertexCentricQueryBuilder method constructQueryWithoutProfile.

protected BaseVertexCentricQuery constructQueryWithoutProfile(RelationCategory returnType) {
    assert returnType != null;
    Preconditions.checkArgument(adjacentVertex == null || returnType == RelationCategory.EDGE, "Vertex constraints only apply to edges");
    if (limit <= 0)
        return BaseVertexCentricQuery.emptyQuery();
    // Prepare direction
    if (returnType == RelationCategory.PROPERTY) {
        if (dir == Direction.IN)
            return BaseVertexCentricQuery.emptyQuery();
        dir = Direction.OUT;
    }
    // Prepare order
    orders.makeImmutable();
    assert orders.hasCommonOrder();
    // Prepare constraints
    And<JanusGraphRelation> conditions = QueryUtil.constraints2QNF(tx, constraints);
    if (conditions == null)
        return BaseVertexCentricQuery.emptyQuery();
    // Don't be smart with query limit adjustments - it just messes up the caching layer and
    // penalizes when appropriate limits are set by the user!
    int sliceLimit = limit;
    // Construct (optimal) SliceQueries
    EdgeSerializer serializer = tx.getEdgeSerializer();
    List<BackendQueryHolder<SliceQuery>> queries;
    if (!hasTypes()) {
        final BackendQueryHolder<SliceQuery> query = new BackendQueryHolder<>(serializer.getQuery(returnType, querySystem), (adjacentVertex == null && dir == Direction.BOTH || returnType == RelationCategory.PROPERTY && dir == Direction.OUT) && !conditions.hasChildren(), orders.isEmpty());
        if (sliceLimit != Query.NO_LIMIT && sliceLimit < Integer.MAX_VALUE / 3) {
            // half will be filtered
            if (dir != Direction.BOTH && (returnType == RelationCategory.EDGE || returnType == RelationCategory.RELATION)) {
                sliceLimit *= 2;
            }
        }
        query.getBackendQuery().setLimit(computeLimit(conditions.size(), sliceLimit));
        queries = ImmutableList.of(query);
        conditions.add(returnType);
        conditions.add(new VisibilityFilterCondition<>(// Need this to filter out newly created invisible relations in the transaction
        querySystem ? VisibilityFilterCondition.Visibility.SYSTEM : VisibilityFilterCondition.Visibility.NORMAL));
    } else {
        final Set<RelationType> ts = new HashSet<>(types.length);
        queries = new ArrayList<>(types.length + 2);
        final Map<RelationType, Interval> intervalConstraints = new HashMap<>(conditions.size());
        final boolean isIntervalFittedConditions = compileConstraints(conditions, intervalConstraints);
        for (Interval pint : intervalConstraints.values()) {
            // Check if one of the constraints leads to an empty result set
            if (pint.isEmpty())
                return BaseVertexCentricQuery.emptyQuery();
        }
        for (String typeName : types) {
            InternalRelationType type = QueryUtil.getType(tx, typeName);
            if (type == null)
                continue;
            Preconditions.checkArgument(!querySystem || (type instanceof SystemRelationType), "Can only query for system types: %s", type);
            if (type instanceof ImplicitKey) {
                throw new UnsupportedOperationException("Implicit types are not supported in complex queries: " + type);
            }
            ts.add(type);
            Direction typeDir = dir;
            if (type.isPropertyKey()) {
                Preconditions.checkArgument(returnType != RelationCategory.EDGE, "Querying for edges but including a property key: %s", type.name());
                returnType = RelationCategory.PROPERTY;
                typeDir = Direction.OUT;
            }
            if (type.isEdgeLabel()) {
                Preconditions.checkArgument(returnType != RelationCategory.PROPERTY, "Querying for properties but including an edge label: %s", type.name());
                returnType = RelationCategory.EDGE;
                if (!type.isUnidirected(Direction.BOTH)) {
                    // Make sure unidirectionality lines up
                    if (typeDir == Direction.BOTH) {
                        if (type.isUnidirected(Direction.OUT))
                            typeDir = Direction.OUT;
                        else
                            typeDir = Direction.IN;
                    } else // Directions are incompatible
                    if (!type.isUnidirected(typeDir))
                        continue;
                }
            }
            if (type.isEdgeLabel() && typeDir == Direction.BOTH && intervalConstraints.isEmpty() && orders.isEmpty()) {
                // TODO: This if-condition is a little too restrictive - we also want to include those cases where
                // there ARE intervalConstraints or orders but those cannot be covered by any sort-keys
                SliceQuery q = serializer.getQuery(type, typeDir, null);
                q.setLimit(sliceLimit);
                queries.add(new BackendQueryHolder<>(q, isIntervalFittedConditions, true));
            } else {
                // Optimize for each direction independently
                Direction[] dirs = { typeDir };
                if (typeDir == Direction.BOTH) {
                    if (type.isEdgeLabel())
                        dirs = new Direction[] { Direction.OUT, Direction.IN };
                    else
                        // property key
                        dirs = new Direction[] { Direction.OUT };
                }
                for (Direction direction : dirs) {
                    /*
                        Find best scoring relation type to answer this query with. We score each candidate by the number
                        of conditions that each sort-keys satisfy. Equality conditions score higher than interval
                        conditions since they are more restrictive. We assign additional points if the sort key
                        satisfies the order of this query.
                        */
                    InternalRelationType bestCandidate = null;
                    double bestScore = Double.NEGATIVE_INFINITY;
                    boolean bestCandidateSupportsOrder = false;
                    PropertyKey[] bestCandidateExtendedSortKey = null;
                    for (InternalRelationType candidate : type.getRelationIndexes()) {
                        // Filter out those that don't apply
                        if (!candidate.isUnidirected(Direction.BOTH) && !candidate.isUnidirected(direction)) {
                            continue;
                        }
                        if (!candidate.equals(type) && candidate.getStatus() != SchemaStatus.ENABLED)
                            continue;
                        boolean supportsOrder = orders.isEmpty() || orders.getCommonOrder() == candidate.getSortOrder();
                        int currentOrder = 0;
                        double score = 0.0;
                        PropertyKey[] extendedSortKey = getExtendedSortKey(candidate, direction, tx);
                        for (PropertyKey keyType : extendedSortKey) {
                            if (currentOrder < orders.size() && orders.getKey(currentOrder).equals(keyType))
                                currentOrder++;
                            Interval interval = intervalConstraints.get(keyType);
                            if (interval == null || !interval.isPoints()) {
                                if (interval != null)
                                    score += 1;
                                break;
                            } else {
                                assert interval.isPoints();
                                score += 5.0 / interval.getPoints().size();
                            }
                        }
                        if (supportsOrder && currentOrder == orders.size())
                            score += 3;
                        if (score > bestScore) {
                            bestScore = score;
                            bestCandidate = candidate;
                            bestCandidateSupportsOrder = supportsOrder && currentOrder == orders.size();
                            bestCandidateExtendedSortKey = extendedSortKey;
                        }
                    }
                    Preconditions.checkArgument(bestCandidate != null, "Current graph schema does not support the specified query constraints for type: %s", type.name());
                    // Construct sort key constraints for the best candidate and then serialize into a SliceQuery
                    // that is wrapped into a BackendQueryHolder
                    EdgeSerializer.TypedInterval[] sortKeyConstraints = new EdgeSerializer.TypedInterval[bestCandidateExtendedSortKey.length];
                    constructSliceQueries(bestCandidateExtendedSortKey, sortKeyConstraints, 0, bestCandidate, direction, intervalConstraints, sliceLimit, isIntervalFittedConditions, bestCandidateSupportsOrder, queries);
                }
            }
        }
        if (queries.isEmpty())
            return BaseVertexCentricQuery.emptyQuery();
        conditions.add(getTypeCondition(ts));
    }
    return new BaseVertexCentricQuery(QueryUtil.simplifyAnd(conditions), dir, queries, orders, limit);
}