Examples with CursorIterator org.neo4j.kernel.impl.coreapi.internal.CursorIterator used on opensource projects

Example 6 with CursorIterator

use of org.neo4j.kernel.impl.coreapi.internal.CursorIterator in project neo4j by neo4j.

the class TransactionImpl method nodesByLabelAndProperty.

private ResourceIterator<Node> nodesByLabelAndProperty(KernelTransaction transaction, int labelId, PropertyIndexQuery query) {
    Read read = transaction.dataRead();
    if (query.propertyKeyId() == TokenRead.NO_TOKEN || labelId == TokenRead.NO_TOKEN) {
        return emptyResourceIterator();
    }
    var index = findUsableMatchingIndex(transaction, SchemaDescriptor.forLabel(labelId, query.propertyKeyId()));
    if (index != IndexDescriptor.NO_INDEX) {
        // Ha! We found an index - let's use it to find matching nodes
        try {
            NodeValueIndexCursor cursor = transaction.cursors().allocateNodeValueIndexCursor(transaction.cursorContext(), transaction.memoryTracker());
            IndexReadSession indexSession = read.indexReadSession(index);
            read.nodeIndexSeek(indexSession, cursor, unconstrained(), query);
            return new CursorIterator<>(cursor, NodeIndexCursor::nodeReference, c -> newNodeEntity(c.nodeReference()), coreApiResourceTracker);
        } catch (KernelException e) {
        // weird at this point but ignore and fallback to a label scan
        }
    }
    return getNodesByLabelAndPropertyWithoutPropertyIndex(transaction, labelId, query);
}

Example 7 with CursorIterator

use of org.neo4j.kernel.impl.coreapi.internal.CursorIterator in project neo4j by neo4j.

the class TransactionImpl method allNodesWithLabel.

private ResourceIterator<Node> allNodesWithLabel(final Label myLabel) {
    KernelTransaction ktx = kernelTransaction();
    int labelId = ktx.tokenRead().nodeLabel(myLabel.name());
    if (labelId == TokenRead.NO_TOKEN) {
        return emptyResourceIterator();
    }
    var index = findUsableMatchingIndex(ktx, SchemaDescriptor.forAnyEntityTokens(EntityType.NODE));
    if (index != IndexDescriptor.NO_INDEX) {
        try {
            var session = ktx.dataRead().tokenReadSession(index);
            var cursor = ktx.cursors().allocateNodeLabelIndexCursor(ktx.cursorContext());
            ktx.dataRead().nodeLabelScan(session, cursor, unconstrained(), new TokenPredicate(labelId));
            return new CursorIterator<>(cursor, NodeIndexCursor::nodeReference, c -> newNodeEntity(c.nodeReference()), coreApiResourceTracker);
        } catch (KernelException e) {
        // ignore, fallback to all node scan
        }
    }
    return allNodesByLabelWithoutIndex(ktx, labelId);
}