Examples with FindTupleMode org.apache.hyracks.storage.am.common.ophelpers.FindTupleMode used on opensource projects

Example 1 with FindTupleMode

use of org.apache.hyracks.storage.am.common.ophelpers.FindTupleMode in project asterixdb by apache.

the class BTreeNSMInteriorFrame method getChildPageId.

@Override
public int getChildPageId(RangePredicate pred) throws HyracksDataException {
    // Trivial case where there is only a child pointer (and no key).
    if (buf.getInt(Constants.TUPLE_COUNT_OFFSET) == 0) {
        return buf.getInt(RIGHT_LEAF_OFFSET);
    }
    // Trivial cases where no low key or high key was given (e.g. during an
    // index scan).
    ITupleReference tuple = null;
    FindTupleMode fsm = null;
    // The target comparator may be on a prefix of the BTree key fields.
    MultiComparator targetCmp = pred.getLowKeyComparator();
    tuple = pred.getLowKey();
    if (tuple == null) {
        return getLeftmostChildPageId();
    }
    if (pred.isLowKeyInclusive()) {
        fsm = FindTupleMode.INCLUSIVE;
    } else {
        fsm = FindTupleMode.EXCLUSIVE;
    }
    // Search for a matching key.
    int tupleIndex = slotManager.findTupleIndex(tuple, frameTuple, targetCmp, fsm, FindTupleNoExactMatchPolicy.HIGHER_KEY);
    int slotOff = slotManager.getSlotOff(tupleIndex);
    // Follow the rightmost (greatest) child pointer.
    if (tupleIndex == slotManager.getGreatestKeyIndicator()) {
        return buf.getInt(RIGHT_LEAF_OFFSET);
    }
    // Deal with prefix searches.
    // slotManager.findTupleIndex() will return an arbitrary tuple matching
    // the given field prefix (according to the target comparator).
    // To make sure we traverse the right path, we must find the
    // leftmost or rightmost tuple that matches the prefix.
    int origTupleOff = slotManager.getTupleOff(slotOff);
    cmpFrameTuple.resetByTupleOffset(buf.array(), origTupleOff);
    int cmpTupleOff = origTupleOff;
    // The answer set begins with the lowest key matching the prefix.
    // We must follow the child pointer of the lowest (leftmost) key
    // matching the given prefix.
    int maxSlotOff = buf.capacity();
    slotOff += slotManager.getSlotSize();
    while (slotOff < maxSlotOff) {
        cmpTupleOff = slotManager.getTupleOff(slotOff);
        frameTuple.resetByTupleOffset(buf.array(), cmpTupleOff);
        if (targetCmp.compare(cmpFrameTuple, frameTuple) != 0) {
            break;
        }
        slotOff += slotManager.getSlotSize();
    }
    slotOff -= slotManager.getSlotSize();
    frameTuple.resetByTupleOffset(buf.array(), slotManager.getTupleOff(slotOff));
    int childPageOff = getLeftChildPageOff(frameTuple);
    return buf.getInt(childPageOff);
}