public KeyIterator getKeys(KeyRangeQuery query, StoreTransaction txh) throws StorageException {
// this query could only be done when byte-ordering partitioner is used
// because Cassandra operates on tokens internally which means that even contiguous
// range of keys (e.g. time slice) with random partitioner could produce disjoint set of tokens
// returning ambiguous results to the user.
Partitioner partitioner = storeManager.getPartitioner();
if (partitioner != Partitioner.BYTEORDER)
throw new PermanentStorageException("getKeys(KeyRangeQuery could only be used with byte-ordering partitioner.");
ByteBuffer start = query.getKeyStart().asByteBuffer(), end = query.getKeyEnd().asByteBuffer();
int limit = (query.hasLimit()) ? query.getLimit() : Integer.MAX_VALUE;