System for controlling concurrent access to data in a database system

A database management system implemented in a digital computer system including a general purpose programmed digital computer on which programs execute to provide access to a stored database, the database management system including a general purpose programmed digital computer on which programs execute to provide access to a stored database configured to manage access to data in a database system, the database management system comprising:

• a data manager configured to:
• receive a lock request for access to data in the database system, the lock request being a request for a page lock or a row lock for a corresponding row or page in the database system containing the data, wherein a table is divided into partitions, wherein each partition contains a portion of the data in the table;
• identify the partition in the database system that contains the row or the page in the database system containing the data;
• determining whether the data has been committed;
• in response to the determination that the data being committed at a time of receiving the lock request, accessing the data without using a partition lock;
• in response to the determination that the data not being committed at a time of receiving the lock request, associate the lock request with a partition lock on the partition that contains the row or the page in the database system containing the data, wherein associating the lock request with the partition lock comprises associating each lock request for the page or the row with the partition lock on the partition that contains the data, the partition lock locking the partition at a lock state that permits serialized access to data in the partition;
• and serial access the data in the partition using the partition lock.

A computer-implemented method for controlling concurrency of access to data in a database system, wherein the computer performs the following functions comprising partitioning a table in the database system into a plurality of partitions:

• receiving a lock request for access to data in the database system, the lock request being a request for a row lock for a corresponding row in the database system containing the data, wherein a table is divided into partitions, wherein each partition contains a portion of the data in the table;
• identifying the partition in the database system that contains the row in the database system containing the data;
• determining whether the data has been committed;
• in response to the determination that the data being committed at a time of receiving the lock request, accessing the data without using a partition lock;
• in response to the determination that the data not being committed at a time of receiving the lock request, associating the lock request with a partition lock on the partition that contains the row in the database system containing the data, wherein associating the lock request with the partition lock comprises associating each lock request for the page or the row with the partition lock on the partition that contains the data, the partition lock directly locking the partition at a lock state that permits serialized access to data in the partition;
• and serially accessing the data in the partition using the partition lock;
• wherein the partition is directly locked without locking the entire database system.

A computer-implemented method for controlling concurrency of access to data in a database system, wherein the computer performs the following functions comprising:

• receiving a lock request for access to data in the database system, the lock request being a request for a row lock for a corresponding row in the database system containing the data, wherein a table is divided into partitions, wherein each partition contains a portion of the data in the table;
• identifying the partition in the database system that contains the row in the database system containing the data;
• associating the lock request with a partition lock on the partition that contains the row in the database system containing the data, wherein associating the lock request with the partition lock comprises associating each lock request for the page or the row with the partition lock on the partition that contains the data, the partition lock directly locking the partition at a lock state that permits serialized access to data in the partition, wherein the lock state protects against interference in the form of updates to the partition;
• serially accessing the data in the partition using the partition lock which includes permitting lock requests access to the partition that are compatible with the lock state;
• wherein the partition is directly locked without locking the entire database system, with the partition lock rather than with a table space lock, and locking the partition with the partition lock only if it cannot be determined whether the data has been committed;
• receiving a lockmax value;
• accumulating for an application, a number of lock requests for access to the data in the database system by the application;
• comparing the number of lock requests with the lockmax value;
• and when the number of lock request equals the lockmax value, escalating the lock state.