Abstract: A weak record locking scheme that, while enforcing serialization of record updates, permits a read to extract data from uncommitted updates. Specifically, records are locked in association with a process or thread performing a lock. When the records affected by a transaction are initially locked for reading or updating, they are locked at the process level. When a particular record is to be read or updated as part of a transaction, it is locked at the thread level. A read transaction that will accept uncommitted changes uses a weak lock to lock the record for reading. A weak lock may be made on a record so long as the record is not already locked for updating at the thread level. While a record is weakly locked for reading, it cannot be locked for updating at the thread level. A record may thus be weakly locked even though the record is locked for updating at the process level by the same process. Weak locking thus preserves serialization of updates, while reducing delays caused by locking conflicts.

Abstract: A weak record locking scheme that, while enforcing serialization of record updates, permits a read to extract data from uncommitted updates. Specifically, records are locked in association with a process or thread performing a lock. When the records affected by a transaction are initially locked for reading or updating, they are locked at the process level. When a particular record is to be read or updated as part of a transaction, it is locked at the thread level. A read transaction that will accept uncommitted changes uses a weak lock to lock the record for reading. A weak lock may be made on a record so long as the record is not already locked for updating at the thread level. While a record is weakly locked for reading, it cannot be locked for updating at the thread level. A record may thus be weakly locked even though the record is locked for updating at the process level by the same process. Weak locking thus preserves serialization of updates, while reducing delays caused by locking conflicts.

Abstract: A method and computer program product are provided for paging control using a reference structure in a computer system. The reference structure is scanned to identify a next selected entry for an IO range building routine. The next selected entry is compared with a set hardlimit value. Responsive to the next selected entry being greater than the hardlimit value, the IO range building routine is exited. A shortlimit value is identified. The next selected entry is compared with the identified shortlimit value. Responsive to the next selected entry being greater than the identified shortlimit value, the IO range building routine is exited. A first array is used for storing entry IDs for selected entries found from scanning the reference structure and a second array is used for tracking blocks of storage used for the selected entries.