Data processing apparatus, method and computer program with optimized key-pointing operation for log record storage

A data processing apparatus has a direct access non-volatile memory storage device having a plurality of extent files for storing log records therein; an allocating unit for allocating a current extent file to be used for storing log records; a writing unit for writing log records into the current extent file until the current extent file cannot store any further log records; and a key-pointing unit for performing a key-pointing operation on the written log records when the writing unit has reached the point where no further log records can be stored in the current extent file.