@Override
public void open(ICursorInitialState initialState, ISearchPredicate searchPred)
throws HyracksDataException, IndexException {
LSMBTreeCursorInitialState lsmInitialState = (LSMBTreeCursorInitialState) initialState;
cmp = lsmInitialState.getOriginalKeyComparator();
includeMemComponent = lsmInitialState.getIncludeMemComponent();
operationalComponents = lsmInitialState.getOperationalComponents();
lsmHarness = lsmInitialState.getLSMHarness();
searchCallback = lsmInitialState.getSearchOperationCallback();
memBTreeAccessor = lsmInitialState.getMemBTreeAccessor();
predicate = (RangePredicate) lsmInitialState.getSearchPredicate();
reusablePred.setLowKeyComparator(cmp);
reusablePred.setHighKey(predicate.getHighKey(), predicate.isHighKeyInclusive());
reusablePred.setHighKeyComparator(predicate.getHighKeyComparator());
int numBTrees = lsmInitialState.getNumBTrees();
rangeCursors = new IIndexCursor[numBTrees];
for (int i = 0; i < numBTrees; i++) {
IBTreeLeafFrame leafFrame =
(IBTreeLeafFrame) lsmInitialState.getLeafFrameFactory().createFrame();
rangeCursors[i] = new BTreeRangeSearchCursor(leafFrame, false);
}
setPriorityQueueComparator();
int cursorIx = 0;
ListIterator<ILSMComponent> btreesIter = operationalComponents.listIterator();
if (includeMemComponent) {
// Open cursor of in-memory BTree at index 0.
memBTreeAccessor.search(rangeCursors[cursorIx], searchPred);
// Skip 0 because it is the in-memory BTree.
++cursorIx;
btreesIter.next();
}
// Open cursors of on-disk BTrees.
int numDiskComponents = includeMemComponent ? numBTrees - 1 : numBTrees;
ITreeIndexAccessor[] diskBTreeAccessors = new ITreeIndexAccessor[numDiskComponents];
int diskBTreeIx = 0;
while (btreesIter.hasNext()) {
BTree diskBTree = (BTree) ((LSMBTreeImmutableComponent) btreesIter.next()).getBTree();
diskBTreeAccessors[diskBTreeIx] =
diskBTree.createAccessor(NoOpOperationCallback.INSTANCE, NoOpOperationCallback.INSTANCE);
diskBTreeAccessors[diskBTreeIx].search(rangeCursors[cursorIx], searchPred);
cursorIx++;
diskBTreeIx++;
}
initPriorityQueue();
proceed = true;
}
@Override
public void nextFrame(ByteBuffer buffer) throws HyracksDataException {
accessor.reset(buffer);
int tupleCount = accessor.getTupleCount();
try {
for (int i = 0; i < tupleCount; i++) {
if (lowKey != null) lowKey.reset(accessor, i);
if (highKey != null) highKey.reset(accessor, i);
rangePred.setLowKey(lowKey, lowKeyInclusive);
rangePred.setHighKey(highKey, highKeyInclusive);
cursor.reset();
indexAccessor.search(cursor, rangePred);
writeSearchResults(accessor, i);
}
} catch (Exception e) {
throw new HyracksDataException(e);
}
}
protected void checkPriorityQueue() throws HyracksDataException, IndexException {
while (!outputPriorityQueue.isEmpty() || needPush == true) {
if (!outputPriorityQueue.isEmpty()) {
PriorityQueueElement checkElement = outputPriorityQueue.peek();
if (proceed && !searchCallback.proceed(checkElement.getTuple())) {
if (includeMemComponent) {
PriorityQueueElement inMemElement = null;
boolean inMemElementFound = false;
// scan the PQ for the in-memory component's element
Iterator<PriorityQueueElement> it = outputPriorityQueue.iterator();
while (it.hasNext()) {
inMemElement = it.next();
if (inMemElement.getCursorIndex() == 0) {
inMemElementFound = true;
it.remove();
break;
}
}
if (inMemElementFound) {
// copy the in-mem tuple
if (tupleBuilder == null) {
tupleBuilder = new ArrayTupleBuilder(cmp.getKeyFieldCount());
}
TupleUtils.copyTuple(tupleBuilder, inMemElement.getTuple(), cmp.getKeyFieldCount());
copyTuple.reset(tupleBuilder.getFieldEndOffsets(), tupleBuilder.getByteArray());
// unlatch/unpin
rangeCursors[0].reset();
// reconcile
if (checkElement.getCursorIndex() == 0) {
searchCallback.reconcile(copyTuple);
} else {
searchCallback.reconcile(checkElement.getTuple());
}
// retraverse
reusablePred.setLowKey(copyTuple, true);
memBTreeAccessor.search(rangeCursors[0], reusablePred);
pushIntoPriorityQueue(inMemElement);
if (cmp.compare(copyTuple, inMemElement.getTuple()) != 0) {
searchCallback.cancel(copyTuple);
continue;
}
} else {
// the in-memory cursor is exhausted
searchCallback.reconcile(checkElement.getTuple());
}
} else {
searchCallback.reconcile(checkElement.getTuple());
}
}
// If there is no previous tuple or the previous tuple can be ignored
if (outputElement == null) {
if (isDeleted(checkElement)) {
// If the key has been deleted then pop it and set needPush to true.
// We cannot push immediately because the tuple may be
// modified if hasNext() is called
outputElement = outputPriorityQueue.poll();
searchCallback.cancel(checkElement.getTuple());
needPush = true;
proceed = false;
} else {
break;
}
} else {
// Compare the previous tuple and the head tuple in the PQ
if (compare(cmp, outputElement.getTuple(), checkElement.getTuple()) == 0) {
// If the previous tuple and the head tuple are
// identical
// then pop the head tuple and push the next tuple from
// the tree of head tuple
// the head element of PQ is useless now
PriorityQueueElement e = outputPriorityQueue.poll();
pushIntoPriorityQueue(e);
} else {
// If the previous tuple and the head tuple are different
// the info of previous tuple is useless
if (needPush == true) {
pushIntoPriorityQueue(outputElement);
needPush = false;
}
proceed = true;
outputElement = null;
}
}
} else {
// the priority queue is empty and needPush
pushIntoPriorityQueue(outputElement);
needPush = false;
outputElement = null;
proceed = true;
}
}
}
protected void setCursor() {
cursor = indexAccessor.createSearchCursor(false);
}