Abstract: Access to a shareable resource between threads is controlled by a lock having shared, optimistic and exclusive modes and maintaining a list of threads requesting ownership of said lock. A shared optimistic mode is provided. A lock state descriptor is provided for each desired change of mode comprising a current mode in which a thread has already acquired the lock. When a thread acquires the lock in shared optimistic mode, other threads are allowed to acquire the lock in shared or optimistic mode. When a thread which acquired the lock in shared optimistic mode wants to acquire the lock in exclusive mode, other threads which have acquired the lock in shared or optimistic mode are prevented from acquiring the lock in exclusive mode until the thread which acquired the lock in shared optimistic mode and requested to acquire the lock in exclusive mode releases the lock.

Abstract: Access to a shareable resource between threads is controlled by a lock having shared, optimistic and exclusive modes and maintaining a list of threads requesting ownership of said lock. A shared optimistic mode is provided. A lock state descriptor is provided for each desired change of mode comprising a current mode in which a thread has already acquired the lock. When a thread acquires the lock in shared optimistic mode, other threads are allowed to acquire the lock in shared or optimistic mode. When a thread which acquired the lock in shared optimistic mode wants to acquire the lock in exclusive mode, other threads which have acquired the lock in shared or optimistic mode are prevented from acquiring the lock in exclusive mode until the thread which acquired the lock in shared optimistic mode and requested to acquire the lock in exclusive mode releases the lock.

Abstract: Embodiments for an approach to managing a relational database. The relational database comprises a first table defining a primary key, and at least one other table with a foreign key constraint referencing the primary key. The data of the first table and at least one other table is divided into a plurality of partitions, each containing data associated with a subset of primary key values. Receiving a partition management policy, defining one or more conditions for the first table and at least one other table and an operation performed on the partitions of the first table and at least one other table. Determining if the first table and at least one other table satisfy the one or more conditions of the partition management policy, if not, performing the operation.

Abstract: An approach to managing a relational database. The relational database comprises a first table defining a primary key, and at least one other table with a foreign key constraint referencing the primary key. The data of the first table and at least one other table is divided into a plurality of partitions, each containing data associated with a subset of primary key values. Receiving a partition management policy, defining one or more conditions for the first table and at least one other table and an operation performed on the partitions of the first table and at least one other table. Determining if the first table and at least one other table satisfy the one or more conditions of the partition management policy, if not, performing the operation.

Abstract: Access to a shareable resource between threads is controlled by a lock having shared, optimistic and exclusive modes and maintaining a list of threads requesting ownership of said lock. A shared optimistic mode is provided. A lock state descriptor is provided for each desired change of mode comprising a current mode in which a thread has already acquired the lock. When a thread acquires the lock in shared optimistic mode, other threads are allowed to acquire the lock in shared or optimistic mode. When a thread which acquired the lock in shared optimistic mode wants to acquire the lock in exclusive mode, other threads which have acquired the lock in shared or optimistic mode are prevented from acquiring the lock in exclusive mode until the thread which acquired the lock in shared optimistic mode and requested to acquire the lock in exclusive mode releases the lock.

Abstract: Access to a shareable resource between threads is controlled by a lock having shared, optimistic and exclusive modes and maintaining a list of threads requesting ownership of said lock. A shared optimistic mode is provided. A lock state descriptor is provided for each desired change of mode comprising a current mode in which a thread has already acquired the lock. When a thread acquires the lock in shared optimistic mode, other threads are allowed to acquire the lock in shared or optimistic mode. When a thread which acquired the lock in shared optimistic mode wants to acquire the lock in exclusive mode, other threads which have acquired the lock in shared or optimistic mode are prevented from acquiring the lock in exclusive mode until the thread which acquired the lock in shared optimistic mode and requested to acquire the lock in exclusive mode releases the lock.

Abstract: Access to a shareable resource between threads is controlled by a lock having shared, optimistic and exclusive modes and maintaining a list of threads requesting ownership of said lock. A shared optimistic mode is provided. A lock state descriptor is provided for each desired change of mode comprising a current mode in which a thread has already acquired the lock. When a thread acquires the lock in shared optimistic mode, other threads are allowed to acquire the lock in shared or optimistic mode. When a thread which acquired the lock in shared optimistic mode wants to acquire the lock in exclusive mode, other threads which have acquired the lock in shared or optimistic mode are prevented from acquiring the lock in exclusive mode until the thread which acquired the lock in shared optimistic mode and requested to acquire the lock in exclusive mode releases the lock.

Abstract: Managing exclusive control of a shareable resource includes publishing a claim non atomically to a lock by a thread that is next to own the lock in an ordered set of threads that have requested to own the lock. The claim includes a structure capable of being read and written only in a single memory access. A determination is made of whether the next owning thread has been pre-empted. Responsive to the determination, the next owning thread of the lock acquires the lock if the next owning thread has not been pre-empted and retries acquisition of the lock if the next owning thread has been pre-empted. Responsive to the next owning thread being pre-empted, a subsequent owning thread acquires the lock unfairly and atomically, consistently modifies the lock such that a next lock owner can determine that the next lock owner has been preempted.

Abstract: Embodiments relate to managing exclusive control of a shareable resource between a plurality of concurrently executing threads. An aspect includes determining the number of concurrently executing threads waiting for exclusive control of the shareable resource. Another aspect includes, responsive to a determination that the number of concurrently executing threads waiting for exclusive control of the shareable resource exceeds a pre-determined value, one or more of said concurrently executing threads terminating its wait for exclusive control of the shareable resource. Another aspect includes, responsive to a determination that the number of concurrently executing threads waiting for exclusive control of the shareable resource is less than a pre-determined value, one or more of said one or more concurrently executing threads which terminated its wait for exclusive control of the shareable resource, restarting a wait for exclusive control of the shareable resource.

Abstract: Provided are techniques for cyclic based data partitioning policy with automatic physical schema management. A data partitioning policy for data is received, wherein the data partitioning policy identifies a condition for automatically implementing the data partitioning policy and criteria for modifying a set of partitions. In response to the condition occurring, the data partitioning policy is automatically applied to select at least one partition from the set of partitions based on the criteria. An operation is performed on the at least one partition to modify the set of partitions.

Abstract: Provided are techniques for cyclic based data partitioning policy with automatic physical schema management. A data partitioning policy for data is received, wherein the data partitioning policy identifies a condition for automatically implementing the data partitioning policy and criteria for modifying a set of partitions. In response to the condition occurring, the data partitioning policy is automatically applied to select at least one partition from the set of partitions based on the criteria. An operation is performed on the at least one partition to modify the set of partitions.

Abstract: An electric machine provided with: a stator, equipped with a single stator winding; at least two shafts, which are independent of one another and are mounted so that they can turn; at least two rotors, which are independent of one another, are magnetically coupled to the stator, and are mounted on the shafts; and a single electronic power converter, which is connected to the stator winding for supplying the stator winding itself with a total electric current.

Abstract: An electric machine provided with: a stator, equipped with a single stator winding; at least two shafts, which are independent of one another and are mounted so that they can turn; at least two rotors, which are independent of one another, are magnetically coupled to the stator, and are mounted on the shafts; and a single electronic power converter, which is connected to the stator winding for supplying the stator winding itself with a total electric current.

Abstract: The method enables a fan rotor to be balanced by the addition of material in at least one selected position on the fan rotor. It is characterized in that the material is added by the application of one or more metal staples.