Instead of repeating these 4 lines of code in multiple places, what do you think about adding a public method to `TSDB`, e.g. `checkNecessaryTablesExist()`?  It would just do:

```java
    public Deferred<ArrayList<Object>> checkNecessaryTablesExist() {
      return Deferred.group(client.ensureTableExists(config.getString("tsd.storage.hbase.data_table")),
                            client.ensureTableExists(config.getString("tsd.storage.hbase.data_table")));
    }
```

or something like that.