Specifies whether to retrieve selected columns only when executing a SELECT statement.
By default, the connector will create a generic scanner to retrieve the results from HBase. This enables all values to be returned without HBase filtering out rows containing empty columns that were selected.
When set to 'True', the connector will only retrieve the selected columns from HBase. Note in this scenario, HBase will not return rows where a selected column is empty. In such a case, this can cause a different number of rows to be returned for various queries. This setting can improve performance but it should only be used when you know that there are no empty values for the selected columns or in the case that you don't want these rows to be returned.