Patent ID: 7707195

Claim:
A database management system that manages a database including a database data page, the database data page providing sub-page storage space, the database management system further managing a plurality of concurrent database transaction requiring a modification of the database data page and storing a respective copy of the database data page in a separate space, the database management system comprising: a processor; and one or more physical computer readable storage media operatively coupled to the processor, the computer-readable storage media having stored thereon computer executable instructions that, when executed by the processor, implement the database management system, including: a database engine that employs an allocation lock to facilitate operations of the concurrent database transactions at a sub-page level during modification of the database data page, the database engine comprising: a lock manage component that facilitates compatibility of operations across the concurrent database transactions, including sub-page locking, and that grants one of the concurrent database transactions an exclusive lock on a first sub-page of the database data page when the one of the concurrent database transactions requests to modify the first sub-page, the exclusive lock permits the one of concurrent database transactions to modify a copy of the first sub-page in its respective copy of the database data page while restricting others of the concurrent database transactions from modifying corresponding copies of the first sub-page in their respective copies of the database data page, but allows the others of the concurrent database transactions to modify other sub-pages, the lock manager component further comprising: an allocation lock component that grants the one of the concurrent database transactions an allocation lock on the database data page when the one of the concurrent database transactions seeks additional space to modify the database data page, wherein the allocation lock permits the one of the concurrent database transactions to acquire additional space on the database data page and to use the additional space in its respective copy of the database data page and allows the others of the concurrent database transactions that do not require additional space on the database data page to effect modifications to their respective copies of the database data page, but prevents the others of the concurrent database transactions from acquiring additional space on the database data page, wherein the allocation lock is distinguished from the exclusion lock; a heap manager component that tracks storage space availability on the database data page to ensure that the concurrent database transactions do not consume all of the storage space on the database data page; and acquiring an intent lock at least in one of a table level, a page level and a database level.