BSTIndex bst = new BSTIndex(conf);
BSTIndexWriter creater = bst.getIndexWriter(new Path(testDir,
"testFindNextKeyValueDescOrder_" + storeType + ".idx"), BSTIndex.TWO_LEVEL_INDEX, keySchema, comp);
creater.setLoadNum(LOAD_NUM);
creater.open();
SeekableScanner scanner = StorageManagerFactory.getSeekableScanner(conf, meta, schema, tablet, schema);
scanner.init();
Tuple keyTuple;