Efficient Top-Down Hierarchical Join On A Hierarchically Clustered Data Stream

An apparatus for conducting a hierarchical join on a hierarchically clustered data stream is disclosed. The apparatus may include a memory storing query conditions that each determine whether a Structured Query Language query is suitable for performing a non-buffering read operation on a hierarchical data storage. A processor in communication with the memory may be configured to receive a Structured Query Language (“SQL”) query from a client device and evaluate the SQL query for one or more of the query conditions stored in the memory. When the processor determines that the SQL query satisfies one or more of the query conditions, the processor may then perform a non-buffering read operation on the hierarchical data storage to obtain a hierarchically clustered data stream. The hierarchically clustered data stream may be evaluated to obtain a plurality of record results, which may be transmitted to the client device.