Hitachi, Ltd.

Hitachi Software Engineering Company, Ltd.

Hideo Munetica

Nobuo Kawamura

Norifumi Nishikawa

Satoshi Wakayama

An area in a page for a tuple-oriented file system is exclusively controlled such that a tuple is added to, deleted from or updated in a page including a tuple area in use, a vacant area having a deleted tuple and an unoccupied area. In the case where a transaction is active for increasing the total size of the vacant area in a given page, the particular vacant area is locked to prevent another active parallel transaction from using the same vacant area. During the time when the transaction for increasing the total size of the vacant area remains active, other transactions can add a tuple to the unoccupied area or update a tuple in use in the same page to the extent that the particular page is not compacted. The transaction for increasing the total size of the vacant area can perform a special compaction for collecting a plurality of discrete vacant areas into a continuous vacant area without increasing the unoccupied area in the page. The roll back operation can thus be executed securely.

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Kobe, Japan

Hideo Munetica