1. An apparatus for conducting a hierarchical join on a hierarchically clustered data stream, the apparatus comprising: a memory configured to store a query condition that determines whether a query is suitable for performing a non-buffering read operation on a hierarchical data storage; and a processor in communication with the memory, the processor being configured to: receive a query; evaluate the query for the query condition; and, when the query satisfies the query condition: perform a non-buffering read operation on the hierarchical data storage based on the read operation query, wherein the non-buffering read operation results in a hierarchically clustered data stream; evaluate the hierarchically clustered data stream according to at least one predicate of the SQL query to obtain a plurality of record results; and transmit the plurality of record results to a client device.