Management of compressed database segments using multiple compression techniques

A computing apparatus comprising:

• one or more non-transitory computer readable storage media;
• a processing system operatively coupled to the one or more non-transitory computer readable storage media;
• and
• program instructions stored on the one or more non-transitory computer readable storage media that, when executed by the processing system, direct the computing apparatus to:
• determine, for a plurality of strings in a segment of a database, a frequency that each string of the plurality of strings appears in the segment;
• identify a first subset of strings in the plurality of strings whose respective frequencies of appearance in the segment satisfy one or more criteria;
• generate a dictionary comprising keys corresponding to for the first subset of strings;
• determine, for symbols in the plurality of strings, a frequency that each symbol of the symbols appears in the segment;
• generate a Huffman data structure based on the frequencies that each symbol of the symbols appears in the segment;
• for strings in the plurality of strings whose respective frequencies of appearance in the segment do not satisfy the one or more criteria, identify a second subset of strings in the plurality of strings with corresponding codes in the Huffman data structure;
• and
• generate a compressed segment by replacing the first subset of strings in the plurality of strings with corresponding keys from the dictionary and replacing the second subset of strings with the corresponding codes in the Huffman data structure.

An apparatus comprising:

• one or more non-transitory computer readable storage media;
• and
• program instructions stored on the one or more non-transitory computer readable storage media that, when executed by a processing system, direct the processing system to:
• determine, for a plurality of strings in a segment, a frequency that each string of the plurality of strings appears in the segment;
• identify a first subset of strings in the plurality of strings whose respective frequencies of appearance in the segment satisfy one or more criteria;
• generate a dictionary comprising keys corresponding to for the first subset of strings;
• determine, for symbols in the plurality of strings, a frequency that each symbol of the symbols appears in the segment;
• generate a Huffman data structure based on the frequencies that each symbol of the symbols appears in the segment;
• for strings in the plurality of strings whose respective frequencies of appearance in the segment do not satisfy the one or more criteria, identifying a second subset of strings in the plurality of strings with corresponding codes in the Huffman data structure;
• and
• generate a compressed segment by replacing the first subset of strings in the plurality of strings with corresponding keys from the dictionary and replacing the second subset of strings with the corresponding codes in the Huffman data structure.