PERFORMING UPDATES ON VARIABLE-LENGTH DATA SEQUENTIALLY STORED AND INDEXED TO FACILITATE REVERSE READING

A system, method, and apparatus are provided for performing update operations on variable-length data records stored and indexed to facilitate reverse reading. Each record contains a key offset for each key field, and the key offset stores a reference (e.g., an offset) to the next most recently stored record that has the same value for the key. Key offsets of a new set of records are configured based on the data index and an assumed write location (e.g., an end offset of the data). The data repository is locked and, if no other intervening records were stored, the new ones are written, the index is updated, and the lock is released. If intervening records were stored, the new set of records is adjusted further based on the current index and the current write location, the records are stored, the index is updated, and the lock is released.