International Business Machines Corporation

Amy Chang

Hui-I Hsiao

Walter Gene Wilson

Timothy Ray Malkemus

Michael Leon Pauser

Yuk Kuen Chan

Anant Deep Jhingran

Daniel J Coyle, Jr

Tu-An Cheng

Debra L Mayhew

Yin Ling Cheung

Lara Hamilton Cone

Provided are techniques for savepoint processing. One of a savepoint statement, a rollback to savepoint statement, and a release savepoint statement is received. It is determined whether to propagate the received one of the savepoint statement, the rollback to savepoint statement, and the release savepoint statement to a data source based on an asymmetrical model in which a nested level of savepoints on a federated server side is capable of being greater than a nested level of savepoints on a data source side and wherein a two-tiered data structure is used to preserve savepoint information in the asymmetrical model. In response to determining that propagation is to occur, the one of the savepoint statement, the rollback to savepoint statement, and the release savepoint statement is propagated to the data source.

Managing and coordinating savepoint functionality in a distributed database system

A dialog window for use in a filtering process provides filtering criteria based upon a limited number of object properties. Each property has an associated criterion input comprising an operator input and a value input which together with the associated property specify a filtering criterion. The dialog window preferably includes a limited number of properties, such as two or three properties, for simplicity and ease of use. Each property further has a selector in the form of a check box by which the user selects the operant filter criteria. The dialog window additionally includes a count button by which the user may update a count display which indicates the number of objects which will be returned using the presently entered filtering criteria.

Graphical filter dialog window system and method for same

A method and system wherein participant node lists are maintained for each individual transaction. In addition, local nodes maintain participant node lists and provide same to coordinating nodes under certain circumstances. The coordinating nodes merge participant node lists and selectively utilize the lists to minimize message duplication. Further, connection node lists for each application are maintained at coordinating nodes and are utilized for application rollback procedures.

Method and system for efficiently coordinating commit processing in a parallel or distributed database system

A three-phase database crash recovery mechanism is detailed including a forward phase, a backward phase, and a third, so-called &ldquo;sideward&rdquo; phase for recovery of transactions which were interrupted at the time of the crash, using Global Transaction IDs to track the status of the transactions at the coordinating and at the participating nodes. Depending upon the status of the transaction at the time of the crash, either a query message to the coordinating node or a vote message to the participating nodes is generated and processed, thereby allowing most interrupted transactions to be completed. Additional implementations are provided for crash recovery, without duplication of efforts, across multiple nodes in a parallel database environment, for cascaded transactions wherein the database recovery at a local node is triggered by database recovery at a remote node in the parallel system, and for concurrent recovery, wherein database recovery is started concurrently at both transaction coordinator and participant nodes.

Method for providing database recovery across multiple nodes

A data processing system and method which manages lock requests at both the transaction and process levels. A lock manager allocates one lock request block (LRB) per process and identifies the ownership of the lock by storing process, transaction and shared IDs in the LRB. The process ID is used to identify which lock to release when a process wants to release the lock before transaction commit while the transaction ID is used to identify all locks to be released at the commit/roll back time of the transaction. The shared ID is a unique value which identifies the lock. The LRB also has a granted transaction mode (GTM) field which stores a value representing the upper bound of the lock modes granted to the transaction. Whenever a lock is granted or released, the GTM of the transaction is recomputed.

Method and system of lock request management in a data processing system

In a system having producer and consumer processes, a producing process look ahead in its outgoing data stream to ensure that there is data available to consumers on all outgoing streams. The producer looks ahead by keeping a data array in its memory space with an entry for each connected consumer. When the outgoing data stream becomes blocked, the producer searches the array for empty connections. Then, the producer scans the outgoing data stream for messages to send over the empty connections and sends such messages. Periodically, the producer checks the original connection to see if the blocking condition has ended.

Method and system for avoiding blocking in a data processing system

In parallel database management systems, database update requests typically result in activity at several nodes. Rollback of all updates is required if the update of any node fails. A coordination process monitors for failure or success of updates. The coordinator further provides for distinguishing activities that have taken place at any given node from the other nodes for different database update requests. Savepoints are local. This allows rollback of a selected update without affecting nodes which did not process the update.

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San Jose, CA, United States of America

Amy Chang