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AssigneeInternational Business Machines Corporation
InventorsSarah Posner, Miroslaw A. Flasza, Jeffrey J. Goss, Matthew A. Huras, Catherine S. McArthur, Lorysa M. Meadowcroft, Michael J. Winer, Roger L. Q. Zheng
Estimating the term…
A system and method handle resource transaction requests. The system marks a waiting transaction request, having an access mode which is incompatible with the access mode of the executing transaction, with an ignore bit, so that a transaction request with an access mode compatible with the access mode of the executing transaction may receive a lock in order to access the resource. The transaction request is then marked with a bypass indicator such that when the executing transactions are finished accessing the resource, the waiting transaction request may be notified that it may have access to the resource. The system includes the ignore bit so that each transaction request that arrives after the ignore bit has been set, does not suffer from a long waiting time before being provided access to the resource.
A method of handling a lock request from a requesting transaction request (transaction B) for additional access to a resource, comprising:
An apparatus for handling a lock request from a requesting transaction request (transaction B) for additional access to a resource, the apparatus comprising:
A computer program product having instruction codes for handling a lock request from a requesting transaction request (transaction B) for additional access to a resource comprising:
A system for handling a lock request from a requesting transaction request (transaction B) for additional access to a resource, comprising:
Dependencies are inferred from the claim text.
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Program synchronisation; Mutual exclusion, e.g. by means of semaphores: mutual exclusion algorithms
Unary operations; Data partitioning operations: efficient disk access during query execution
Indexing scheme relating to G06F9/52: manager
Indexing scheme relating to G06F9/52: mode
Term ended 12 Dec 2023 (estimated)
The present application claims the priority of Canadian Patent Application Serial No. 2,369,621, titled “Method and Apparatus for Handling Resource Transaction Requests,” filed on Jan. 25, 2002, which is incorporated herein by reference in its entirety.
The present invention relates in general to the field of resource manipulation, and more specifically to a method and apparatus for handling resource transaction requests.
In the field of database technology, resources, generally in the form of a row within a table, are accessed to be written to or read from. In most cases, the resource is individually accessed by queued transactions which are arranged in a First-In-First-Out (FIFO) manner. At any time, the resource may be accessed by multiple transactions which have concurrently requested access to the resource provided the transactions have compatible access modes.
These and other features of the preferred embodiments of the invention will become more apparent in the following detailed description in which reference is made to the appended drawings wherein:
FIG. 1 is a schematic diagram of devices accessing a resource;
FIG. 2 is a first example of a schematic diagram of transaction requests;
Turning to FIG. 1, devices 2, such as processors or scanners send transaction requests to a lock manager 14 associated with a resource 10 they wish to access. As used herein, a transaction request may include a lock request. The transaction requests are stored in a list 4 to keep track of all the transaction requests received by the lock manager 14. Although only three devices 2 are shown, it should be understood that any number of devices 2 may send transaction requests to the lock manager 14. A requester 16 sets an overall ignore indicator, such as an overall ignore bit, as well as individual ignore indicators, such as an ignore indicator bits.
Turning to FIG. 2, the resource 10 generally has several existing or prior transaction requests 12. These transaction requests 12 are stored in the list 4 of FIG. 1, in order to monitor access of devices to the resource 10. It will be understood that the resource 10 is preferably a row of information within a table.
The transaction requests 12 request access to the resource in order for their associated devices to perform certain instructions such as updates, reads or writes on the resource. As an illustration, the resource 10 of FIG. 2 presently has four existing transaction requests 12, T1, T2, T3, and T4. Any new, or requesting, transaction requests 13 are forwarded to, and monitored by the lock manager 14 to determine if these new requests 13 are compatible with existing transaction requests, such as executing or waiting.