Examples with VirtualNodeSet org.exist.dom.persistent.VirtualNodeSet used on opensource projects

Example 6 with VirtualNodeSet

use of org.exist.dom.persistent.VirtualNodeSet in project exist by eXist-db.

the class Predicate method recomputeExecutionMode.

private Tuple2<ExecutionMode, Sequence> recomputeExecutionMode(final Sequence contextSequence, final Expression inner) throws XPathException {
    ExecutionMode recomputedExecutionMode = executionMode;
    Sequence innerSeq = null;
    // Atomic context sequences :
    if (Type.subTypeOf(contextSequence.getItemType(), Type.ATOMIC)) {
        // the inner sequence
        if (executionMode == NODE && !(contextSequence instanceof VirtualNodeSet)) {
            // (1,2,2,4)[.]
            if (Type.subTypeOfUnion(contextSequence.getItemType(), Type.NUMBER)) {
                recomputedExecutionMode = POSITIONAL;
            } else {
                recomputedExecutionMode = BOOLEAN;
            }
        }
        // If there is no dependency on the context item, try a positional promotion
        if (executionMode == BOOLEAN && !Dependency.dependsOn(inner, Dependency.CONTEXT_ITEM) && // computation should now be better
        !((inner instanceof GeneralComparison) && ((GeneralComparison) inner).invalidNodeEvaluation)) {
            innerSeq = inner.eval(contextSequence);
            // Only if we have an actual *singleton* of numeric items
            if (innerSeq.hasOne() && Type.subTypeOfUnion(innerSeq.getItemType(), Type.NUMBER)) {
                recomputedExecutionMode = POSITIONAL;
            }
        }
    } else if (executionMode == NODE && !contextSequence.isPersistentSet()) {
        recomputedExecutionMode = BOOLEAN;
    } else {
        if (executionMode == BOOLEAN && !Dependency.dependsOn(inner, Dependency.CONTEXT_ITEM)) {
            /*
                 *
                 * WARNING : this sequence will be evaluated with
                 * preloadable nodesets !
                 */
            innerSeq = inner.eval(contextSequence);
            // We are now sure of the inner sequence return type
            if (Type.subTypeOf(innerSeq.getItemType(), Type.NODE) && innerSeq.isPersistentSet()) {
                recomputedExecutionMode = NODE;
            // Try to promote a boolean evaluation to a positional one
            // Only if we have an actual *singleton* of numeric items
            } else if (innerSeq.hasOne() && Type.subTypeOfUnion(innerSeq.getItemType(), Type.NUMBER)) {
                recomputedExecutionMode = POSITIONAL;
            }
        }
    }
    return Tuple(recomputedExecutionMode, innerSeq);
}

Example 7 with VirtualNodeSet

use of org.exist.dom.persistent.VirtualNodeSet in project exist by eXist-db.

the class GeneralComparison method quickNodeSetCompare.

/**
 * Optimized implementation: first checks if a range index is defined on the nodes in the left argument.
 * Otherwise, fall back to {@link #nodeSetCompare(NodeSet, Sequence)}.
 *
 * @param   contextSequence  DOCUMENT ME!
 *
 * @return  DOCUMENT ME!
 *
 * @throws  XPathException  DOCUMENT ME!
 */
protected Sequence quickNodeSetCompare(Sequence contextSequence) throws XPathException {
    if (context.getProfiler().isEnabled()) {
        context.getProfiler().message(this, Profiler.OPTIMIZATION_FLAGS, "OPTIMIZATION CHOICE", "quickNodeSetCompare");
    }
    final long start = System.currentTimeMillis();
    // get the NodeSet on the left
    final Sequence leftSeq = getLeft().eval(contextSequence);
    if (!leftSeq.isPersistentSet()) {
        return (genericCompare(leftSeq, contextSequence, null));
    }
    final NodeSet nodes = leftSeq.isEmpty() ? NodeSet.EMPTY_SET : (NodeSet) leftSeq;
    // nothing on the left, so nothing to do
    if (!(nodes instanceof VirtualNodeSet) && nodes.isEmpty()) {
        // Well, we might discuss this one ;-)
        hasUsedIndex = true;
        return (Sequence.EMPTY_SEQUENCE);
    }
    // get the Sequence on the right
    final Sequence rightSeq = getRight().eval(contextSequence);
    // nothing on the right, so nothing to do
    if (rightSeq.isEmpty()) {
        // Well, we might discuss this one ;-)
        hasUsedIndex = true;
        return (Sequence.EMPTY_SEQUENCE);
    }
    // get the type of a possible index
    final int indexType = nodes.getIndexType();
    // remember that Type.ITEM means... no index ;-)
    if (indexType != Type.ITEM) {
        if (LOG.isTraceEnabled()) {
            LOG.trace("found an index of type: {}", Type.getTypeName(indexType));
        }
        boolean indexScan = false;
        boolean indexMixed = false;
        QName myContextQName = contextQName;
        if (contextSequence != null) {
            final IndexFlags iflags = checkForQNameIndex(idxflags, context, contextSequence, myContextQName);
            boolean indexFound = false;
            if (!iflags.indexOnQName) {
                // if myContextQName != null and no index is defined on
                // myContextQName, we don't need to scan other QName indexes
                // and can just use the generic range index
                indexFound = myContextQName != null;
                if (iflags.partialIndexOnQName) {
                    indexMixed = true;
                } else {
                    // set myContextQName to null so the index lookup below is not
                    // restricted to that QName
                    myContextQName = null;
                }
            }
            if (!indexFound && (myContextQName == null)) {
                // we need to check them all
                if (iflags.hasIndexOnQNames) {
                    indexScan = true;
                }
            // else use range index defined on path by default
            }
        } else {
            return (nodeSetCompare(nodes, contextSequence));
        }
        // Get the documents from the node set
        final DocumentSet docs = nodes.getDocumentSet();
        // Holds the result
        NodeSet result = null;
        // Iterate through the right hand sequence
        for (final SequenceIterator itRightSeq = Atomize.atomize(rightSeq).iterate(); itRightSeq.hasNext(); ) {
            // Get the index key
            Item key = itRightSeq.nextItem();
            // if key has truncation, convert it to string
            if (truncation != StringTruncationOperator.NONE) {
                if (!Type.subTypeOf(key.getType(), Type.STRING)) {
                    LOG.info("Truncated key. Converted from {} to xs:string", Type.getTypeName(key.getType()));
                    // truncation is only possible on strings
                    key = key.convertTo(Type.STRING);
                }
            } else // TODO : use Type.isSubType() ??? -pb
            if (key.getType() != indexType) {
                // try to convert the key to the index type
                try {
                    key = key.convertTo(indexType);
                } catch (final XPathException xpe) {
                    // Could not convert the key to a suitable type for the index, fallback to nodeSetCompare()
                    if (context.getProfiler().isEnabled()) {
                        context.getProfiler().message(this, Profiler.OPTIMIZATION_FLAGS, "OPTIMIZATION FALLBACK", "Falling back to nodeSetCompare (" + xpe.getMessage() + ")");
                    }
                    if (LOG.isTraceEnabled()) {
                        LOG.trace("Cannot convert key: {} to required index type: {}", Type.getTypeName(key.getType()), Type.getTypeName(indexType));
                    }
                    return (nodeSetCompare(nodes, contextSequence));
                }
            }
            // If key implements org.exist.storage.Indexable, we can use the index
            if (key instanceof Indexable) {
                if (LOG.isTraceEnabled()) {
                    LOG.trace("Checking if range index can be used for key: {}", key.getStringValue());
                }
                final Collator collator = ((collationArg != null) ? getCollator(contextSequence) : null);
                if (Type.subTypeOf(key.getType(), indexType)) {
                    if (truncation == StringTruncationOperator.NONE) {
                        if (LOG.isTraceEnabled()) {
                            LOG.trace("Using range index for key: {}", key.getStringValue());
                        }
                        // key without truncation, find key
                        context.getProfiler().message(this, Profiler.OPTIMIZATIONS, "OPTIMIZATION", "Using value index '" + context.getBroker().getValueIndex().toString() + "' to find key '" + Type.getTypeName(key.getType()) + "(" + key.getStringValue() + ")'");
                        NodeSet ns;
                        if (indexScan) {
                            ns = context.getBroker().getValueIndex().findAll(context.getWatchDog(), relation, docs, nodes, NodeSet.ANCESTOR, (Indexable) key);
                        } else {
                            ns = context.getBroker().getValueIndex().find(context.getWatchDog(), relation, docs, nodes, NodeSet.ANCESTOR, myContextQName, (Indexable) key, indexMixed);
                        }
                        hasUsedIndex = true;
                        if (result == null) {
                            result = ns;
                        } else {
                            result = result.union(ns);
                        }
                    } else {
                        // key with truncation, match key
                        if (LOG.isTraceEnabled()) {
                            context.getProfiler().message(this, Profiler.OPTIMIZATIONS, "OPTIMIZATION", "Using value index '" + context.getBroker().getValueIndex().toString() + "' to match key '" + Type.getTypeName(key.getType()) + "(" + key.getStringValue() + ")'");
                        }
                        if (LOG.isTraceEnabled()) {
                            LOG.trace("Using range index for key: {}", key.getStringValue());
                        }
                        try {
                            NodeSet ns;
                            final String matchString = key.getStringValue();
                            final int matchType = getMatchType(truncation);
                            if (indexScan) {
                                ns = context.getBroker().getValueIndex().matchAll(context.getWatchDog(), docs, nodes, NodeSet.ANCESTOR, matchString, matchType, 0, true, collator, truncation);
                            } else {
                                ns = context.getBroker().getValueIndex().match(context.getWatchDog(), docs, nodes, NodeSet.ANCESTOR, matchString, myContextQName, matchType, collator, truncation);
                            }
                            hasUsedIndex = true;
                            if (result == null) {
                                result = ns;
                            } else {
                                result = result.union(ns);
                            }
                        } catch (final EXistException e) {
                            throw (new XPathException(this, e));
                        }
                    }
                } else {
                    // our key does is not of the correct type
                    if (context.getProfiler().isEnabled()) {
                        context.getProfiler().message(this, Profiler.OPTIMIZATION_FLAGS, "OPTIMIZATION FALLBACK", "Falling back to nodeSetCompare (key is of type: " + Type.getTypeName(key.getType()) + ") whereas index is of type '" + Type.getTypeName(indexType) + "'");
                    }
                    if (LOG.isTraceEnabled()) {
                        LOG.trace("Cannot use range index: key is of type: {}) whereas index is of type '{}", Type.getTypeName(key.getType()), Type.getTypeName(indexType));
                    }
                    return (nodeSetCompare(nodes, contextSequence));
                }
            } else {
                // our key does not implement org.exist.storage.Indexable
                if (context.getProfiler().isEnabled()) {
                    context.getProfiler().message(this, Profiler.OPTIMIZATION_FLAGS, "OPTIMIZATION FALLBACK", "Falling back to nodeSetCompare (key is not an indexable type: " + key.getClass().getName());
                }
                if (LOG.isTraceEnabled()) {
                    LOG.trace("Cannot use key which is of type '{}", key.getClass().getName());
                }
                return (nodeSetCompare(nodes, contextSequence));
            }
        }
        if (context.getProfiler().traceFunctions()) {
            context.getProfiler().traceIndexUsage(context, PerformanceStats.RANGE_IDX_TYPE, this, PerformanceStats.BASIC_INDEX, System.currentTimeMillis() - start);
        }
        return (result);
    } else {
        if (LOG.isTraceEnabled()) {
            LOG.trace("No suitable index found for key: {}", rightSeq.getStringValue());
        }
        // no range index defined on the nodes in this sequence, so fallback to nodeSetCompare
        if (context.getProfiler().isEnabled()) {
            context.getProfiler().message(this, Profiler.OPTIMIZATION_FLAGS, "OPTIMIZATION FALLBACK", "falling back to nodeSetCompare (no index available)");
        }
        return (nodeSetCompare(nodes, contextSequence));
    }
}