摘要:
The invention relates to the recovery of data in a database of database records, following a failure of a media containing said database. The data recovery uses a backup of the database and a log of log records detailing any changes in the database which are not captured in the backup. The log is replayed starting with the most recent log record. It is the determined for each successive log record, that relates to an operation on a database record, whether processing the log record will result in the most recent state of the corresponding database record, and if so, the log record is processed. Subsequently additional data is restored from the backup.
摘要:
A data processing system (100) and method for creating a fuzzy backup (116) only of objects older than a predetermined threshold, and restoring from the fuzzy backup and from a record log (114) replayed from a time equal to the predetermined threshold before the fuzzy backup start time.This provides advantages of reduced resource cost for the fuzzy backup and reduced restore time.
摘要:
Provided are a method, computer program product and system for providing indexed queue support for efficient retrieval of messages from a queue. An index key for expediting message retrieval is assigned to a message when the operation of placing the message on a queue is committed. The index key assigned at commit time comprises an attribute (such as a message ID or correlation ID) specified by the sending application program, which placed the message on the queue. This deferred assignment of an index key until commit time means that the index key can be used to search for messages having the particular attribute without any possibility of identifying messages for retrieval before the messages have been committed. This maintains transactional requirements of a transaction-oriented messaging system which requires a message to only be made available for retrieval by receiver application programs after the sender application's put operation has committed.
摘要:
A data processing arrangement (100) and method for fuzzy backup and restore of MQSeries shared queues held in coupling facility list structure (106). Periodically backups are taken of the data held in the CF list structure by backing up messages in the sequence uncommitted puts (220), committed puts (230), uncommitted gets (240) and expired messages (250), whereby all messages may be backed up in the backup means except for exceptions which are recorded in the record log. In the event of media failure of the coupling facility, data can be restored by restoring messages in the sequence restoring messages from the backup means (320), replaying messages from the record log means (340) and determining final disposition of messages from replay of the record log means (350). This provides the advantage of allowing the number of log records written to be reduced.
摘要:
Provided are a computer program, method and system providing simplified administration of groups of computer programs. Command target qualifiers are defined which enable a command to be targeted at either an individual computer program or all members of a group of computer programs. Additionally, scope parameters are defined which enable a command to be targeted at specific computer system resources managed by the computer programs within the group. The computer system resources which are to be accessible to all members of a group have an associated scope parameter defining shared or group access and are held in shared storage, whereas computer system resources to be accessed by only one computer program in the group have a corresponding scope parameter and are held in the local storage of the individual computer program. The invention enables a reduction of the time taken to perform administration and control operations for the group and reduces the risk of inconsistent specification of commands that can arise when a system administrator is required to repeat entry of a command several times.
摘要:
A data processing system for message handling comprises a coupling facility for receiving messages, the coupling facility arranged to maintain a queue of messages, and a database for storing messages. A component, such as a server, of the system is arranged to detect that a message is of a size above a predetermined threshold, and therefore stores this larger message in the database and enters a proxy in the queue of messages.
摘要:
The present invention relates to a data processing system and method as well as to a computer program product for realizing such a data processing system and method. Conventionally, access to system resources is controlled within, for example, MQSeries, via security settings or security definition contained within profiles that are used to initialize a data processing system. Typically, each computer program or user has associated access permissions which may, from time to time, be varied by a system administrator. It will be appreciated that to issue on a resource by resource or user by user basis individual changes to access permission would require a significant amount of work. Suitably, the present invention provides a system and method for implementing grouping of security access control for a number of resources or users. Therefore, a single security change request can be used to effect a change of access permissions associated with a number of separate or at least closely coupled resources.
摘要:
Provided are methods, data processing systems, recovery components and computer programs for recovering from storage failures affecting data repositories. At least a part of the recovery processing is performed while the data repositories are able to receive new data and to allow retrieval of such new data. Although new data items may be received into the repository and retrieved therefrom during recovery processing, updates to the data repository which were performed before the failure and which are then restored to the repository by the recovery processing are restored within a recovery unit of work and are inaccessible to processes other than the recovery process until successful completion of the recovery unit of work. The recovery processing ensures that the recovered repository is consistent with the state of the repository at the time of the failure, but is available for addition and retrieval of new data items before completion of the recovery processing.
摘要:
The invention provides a restart mechanism within a data processing system for restarts following a failure. The mechanism is provided in persistent storage as a recovery log containing recovery log records which can be used during recovery from the failure of the data processing system. The log records relate to units of work undertaken by the data processing system, and the mechanism retrieves, from the recovery log, a recovery log record relating to a unit of work, determines whether or not the unit of work meets at least one predetermined criterion, and performs a recovery process if the unit of work meets the predetermined criterion.
摘要:
Provided are methods, data processing systems, recovery components and computer programs for recovering from storage failures affecting data repositories. At least a part of the recovery processing is performed while the data repositories are able to receive new data and to allow retrieval of such new data. Although new data items may be received into the repository and retrieved therefrom during recovery processing, updates to the data repository which were performed before the failure and which are then restored to the repository by the recovery processing are restored within a recovery unit of work and are inaccessible to processes other than the recovery process until successful completion of the recovery unit of work. The recovery processing ensures that the recovered repository is consistent with the state of the repository at the time of the failure, but is available for addition and retrieval of new data items before completion of the recovery processing.