International Business Machines Corporation

Rajesh C Lalgowdar

Lohitashwa Thyagaraj

Sanjay Mecheri Kesavan

Venkataraghavan Lakshminarayanachar

Justin T Fries

Ian Robinson

Chethan Bhat

Trent Gray-Donald

Sonali Samantaray

Release and re-acquisition of each of a first shared lock on an outer database ownership table and a second shared lock on an inner database ownership table is alternated by a messaging engine processor that executes a messaging engine to permit database maintenance operations to be performed while maintaining the ownership of the database. At least one period of inactivity of both the outer database ownership table and the inner database ownership table is provided that allows at least one database tool to execute to perform at least one database maintenance task during the execution of the messaging engine.

Management of long-running locks and transactions on database tables

Applications retrieve physical messages from one of either a co-located, passive messaging engine within the same datacenter as the application, or a nearest passive messaging engine from a different datacenter instead of from the active messaging engine. In that way, the active messaging engine does not deliver the physical message directly from its local storage.

Message retrieval in a distributed computing network

An exclusive lock is acquired on each of an outer database ownership table and an inner database ownership table to obtain ownership of a database. The exclusive locks are converted to a pair of overlapping shared locks on each of the outer database ownership table and the inner database ownership table, where release and re-acquisition of each of the pair of overlapping shared locks on the outer database ownership table and the inner database ownership table permits database maintenance operations to be performed while maintaining the ownership of the database.

A method is provided for providing unit of work continuity between a client device and a server when the client device initially fails to complete an ongoing unit of work. The method includes temporarily storing, in a temporary storage location in the server, in-doubt messages sent to the server for the ongoing unit of work, when the client device disconnects from the server without committing the ongoing unit of work so that the client device does not have to resend the in-doubt messages to the server. The method further includes utilizing unique hash-codes to identify the in-doubt messages the client device had earlier sent so that the server can retrieve the in-doubt messages from the temporary storage location and include the in-doubt messages as part of the ongoing unit of work to be committed by the client device. The ongoing unit of work is only part of an entire transaction.

Providing unit of work continuity in the event initiating client fails over

Establishment of an exclusive lock on each of an outer database ownership table and an inner database ownership table is attempted. In response to establishing the exclusive lock on each of the outer database ownership table and the inner database ownership table, a switch is made to a pair of overlapping shared locks on each of the outer database ownership table and the inner database ownership table. Release and re-acquisition of each of the pair of overlapping shared locks on the outer database ownership table and the inner database ownership table is alternated.

According to one exemplary embodiment, a method for selectively resending a first message in a publish-subscribe message distribution model is provided. The method may include receiving the first message having a first message ID associated with the first message. The method may include sending the first message to a plurality of subscribers. The method may include receiving a rolled back first message. The method may include determining if the first message ID matches a second message ID associated with a second message. The method may include creating a first subscriber list associated with the first message. The method may include storing the first message in a data structure. The method may include appending a second subscriber list associated with the second message with a subscriber. The method may include sending the second message to the first subscriber or the first message to the first subscriber.

Selective message republishing to subscriber subsets in a publish-subscribe model

Creating message files in a publication subscription computer system by: (i) receiving data corresponding to a first message; (ii) receiving a list of subscribers that subscribe to a topic of the first message; and (iii) creating a digital data file that includes a payload data and a consumption metadata. The payload data includes content data corresponding to the first message. The consumption metadata includes data relating to whether one or more subscribers of the list of subscribers will potentially consume the first message at a later period in time from the time of receiving the content data corresponding to the first message.

Optimizing storage in a publish / subscribe environment

Embodiments of the present invention disclose a method, computer program product, and computer system for prioritizing messages based on subscriber preferences. In an embodiment of the invention, an application server computer determines that a subscriber is subscribed to at least one topic space. The application server computer receives one or more topic priority preferences from the subscriber, and a plurality of messages from the at least one topic space. The application server computer prioritizes the plurality of messages based on the received topic priority preference, and sends the prioritized plurality of messages to the subscriber.

Subscriber based priority of messages in a publisher-subscriber domain

Resource reservation request information originated by a client application during a first phase of a distributed multi-phase transaction is received at a processor. The resource reservation request information specifies a first resource the client application intends to access during a first subsequent phase of the distributed multi-phase transaction after the first phase of the distributed multi-phase transaction is completed. The requested first resource is reserved on behalf of the client application. A transaction weighted priority is assigned to the distributed multi-phase transaction of the client application based upon a stage of completion of the distributed multi-phase transaction.

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Bengaluru, India

Rajesh C Lalgowdar