Similarity similarity = _tableSimilarity.get(table);
if (similarity == null) {
TableDescriptor tableDescriptor = _clusterStatus.getTableDescriptor(true, _cluster, table);
String similarityClass = tableDescriptor.similarityClass;
if (similarityClass == null) {
similarity = new FairSimilarity();
} else {
similarity = getInstance(similarityClass, Similarity.class);
}
_tableSimilarity.put(table, similarity);
}