System and program for joining source table rows with target table rows

An article of manufacture for directing a data processing system to join rows associated with a column of a source table with rows associated with a column of a target table, the data processing system including a source node containing the source table and including a target node of a plurality of target nodes, the target node containing the target table, the article of manufacture comprising:

• a non-transitory program usable medium embodying one or more instructions executable by the data processing system, the one or more instructions comprising:
• data processing system executable instructions for generating a reduced representation of selected rows associated with the column of the source table, and generating a representation of the column of the target table;
• data processing system executable instructions for filtering the generated reduced representation of selected rows associated with the column of the source table through the generated representation of the column of the target table, and for generating a bit map with the filtered generated reduced representation of selected rows which identifies source table rows that do not have to be joined with the target table;
• and
• data processing system executable instructions for joining, to the rows associated with the column of the target table, the rows associated with the column of the source table minus the filtered generated reduced representation of selected rows,
• wherein the generating the reduced representation of the selected rows associated with the column of the source table comprises:
• applying a hash function against the column to obtain hash codes, the column being associated with selected rows identifying the source table rows;
• storing the hash codes in a hash code buffer, the hash code buffer representing the source table rows to be sent to the corresponding target node of the plurality of target nodes;
• determining whether data in a data buffer of the source node reaches a threshold;
• asynchronously sending, in response to the threshold being reached, the hash code buffer to the corresponding target node and obtaining and storing other hash codes in another hash code buffer to be sent to another target node,
• wherein the hash function maps a joining key to a hash code, and
• wherein the target node generates the bit map by matching the hash codes with a bit filter associated with the target table, the bit map identifying the source table rows that are not to be joined with the target table rows.