File collectionTgz = new File(voltDbRootPath, prefix + ".tgz");
assertTrue(collectionTgz.exists());
File collectionDecompressed = new File(voltDbRootPath, prefix);
TarReader tarReader = new TarReader(collectionTgz, TarReader.OVERWRITE_MODE, null, null, collectionDecompressed);
tarReader.read();
assertTrue(collectionDecompressed.exists());
return collectionDecompressed;
}