International Business Machines Corporation

Michael J Shershin

Robert O Dryfoos

Christopher Daniel Filachek

Mark Richard Gambino

Robert A Blackburn

Steven Edwin Roach

Gabriel Nieves

Jason A Keenaghan

Mark A Lehrer

Kenneth H Warner

Daniel Howard Jacobs

According to at least one embodiment, a method, a computer system, and a computer program product for minimizing I/O operations when validating databases are provided. The present invention may include creating a corresponding system-managed chain database for an application database, the chain database comprising a list of one or more dynamically allocated records, if present, for one or more fixed entries in the application database, wherein each of the fixed entries comprises a respective chain database array item in the chain database; scanning, via a validation utility, one or more chain database array items; marking each of the one or more dynamically allocated records listed in the chain database for the fixed entries as found; and checking, via an indicator with various states, if the one or more dynamically allocated records for the one or more fixed entries are listed in the respective chain database array item.

Minimizing I/O operations when validating flat databases

Management of hierarchical process groups is provided. Aspects include creating a group identifier having an associated set of resource limits for shared resources of a processing system. A process is associated with the group identifier. A hierarchical process group is created including the process as a parent process and at least one child process spawned from the parent process, where the at least one child process inherits the group identifier. A container is created to store resource usage of the hierarchical process group and the set of resource limits of the group identifier. The set of resources associated with the hierarchical process group is used to collectively monitor resource usage of processes. A resource allocation adjustment action is performed in the processing system based on determining that an existing process exceeds a process resource limit or the hierarchical process group exceeds at least one of the set of resource limits.

Hierarchical process group management

Management of hierarchical process groups is provided. Aspects include creating a group identifier having an associated set of resource limits for shared resources of a processing system. A process is associated with the group identifier. A hierarchical process group is created including the process as a parent process and at least one child process spawned from the parent process, where the at least one child process inherits the group identifier. A container is created to store resource usage of the hierarchical process group and the set of resource limits of the group identifier. The set of resources associated with the hierarchical process group is used to collectively monitor resource usage of a plurality of processes in the hierarchical process group.

A method and system is disclosed for dispatching tasks to multiple processors that all share a shared memory. A composite queue size for multiple work queues each having an associated processor is determined. A queue availability flag is stored in shared memory for each processor work queue and is set based upon the composite queue size and the size of the work queue for that processor. Each queue availability flag indicates availability or unavailability of the work queue to accept new tasks. A task is placed in a selected work queue based on that work queue having an associated queue availability flag indicating availability to accept new tasks. The data associated with task dispatching is maintained so as to increase the likelihood that valid copies of the data remain present in each processor's local cache without requiring updating do to their being changed by other processors.

Task dispatching based on composite queue size and upper and lower compare values

A method and system is disclosed for selecting a work queue associated with a processor within a multiple processor architecture to assign a new task. A local and a remote queue availability flag is maintained to indicate a relative size of work queues, in relationship to a mean queue size, for each processor in a multiple processor architecture. In determining to which processor to assign a task, the processor evaluates its own queue size by examining its local queue availability flag and evaluates other processor's queue sizes by examining their remote queue availability flags. The local queue availability flags are maintained asynchronously from task assignment. Remote flags are maintained at time of task assignment. The presented algorithm provides improved local processor queue size determinations in systems where task distribution processes execute with lower priorities that other tasks.

Work queue selection on a local processor within a multiple processor architecture

A method for identifying a set of records in a database for relocation during an on-line database reorganization (ODBR) process. The relocating includes, for each of the records in the set: requesting a record reorganization lock (RRL) on the record, receiving the RRL, retrieving data from the current location of the record, storing the data in the new location of the record, and releasing the RRL. A request is received to update a target record in the set of records with updated data. The receiving of the request is from an application and overlaps in time with at least a portion of the relocating. Independent of the application, a RRL is received on the target record and the target record is updated by writing target data to the target record in the current location and writing the target data to the target record in the new location.

Collision detection and data corruption protection during an on-line database reorganization

Dynamically allocated memory is managed in real-time. This real-time management capability enables an invalid access of the dynamically allocated memory to be detected at the time the invalid access occurs, rather than at some later point in time. This real-time management capability can be dynamically activated/deactivated on a per process basis.

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Poughkeepsie, NY, United States of America

Michael J Shershin