Hierarchical data compression and computation

A method of hierarchical compression comprising:

• creating a compression hierarchy of compression nodes, wherein each compression node is associated with a compression operation to produce compressed data, and wherein creating the compression hierarchy of compression nodes comprises:
• creating a run length encoding compression node in the compression hierarchy;
• determining a path of one or more compression nodes through said compression hierarchy, based upon compression statistics, to compress data;
• and
• compressing the data by the compression nodes of the path, wherein compressing the data comprises:
• performing part of a join operation on the data using the run length encoding compression node, wherein the join operation is performed by applying input data to a values field of the run length encoding compression node and by applying repeat counts to a lengths field of the run length encoding compression node.