Abstract: A system, method, computer program and system for suspending a result set and continuing from a suspended result set for transparent session migration is disclosed. The rows from a row source are suspended into storage, so that after session migration, the client fetches can transparently continue from the suspended result set.

Abstract: A method and apparatus for efficiently processing data requests in a network oriented n-tier database environment is presented. According to one embodiment of the invention, certain or all data from the tables of a database server device can be maintained in tables on the client device in a client side database cache server system. This local cache allows the network oriented n-tier database system to eliminate the expense of repetitive network transmissions to respond to duplicate queries for the same information. Additionally, the local client device may also keep track of what data is cached on peer network nodes. This allows the client to request that data from a peer database cache server and off load that burden from the database server device. Moreover, the local client may also keep statistics regarding the frequency of requested data in order to optimize the data set maintained in the local database cache server.

Abstract: An approach migrates database sessions from a database server on which performance and resource availability requirements are not being met to another database server. Because workload is removed from the database server not meeting these requirements, improved performance there is promoted. Furthermore, the approach switches the users in a way that attempts to keep performance and resource availability levels at the database server receiving the database sessions within goals for performance and resource availability.

Abstract: A computer-implemented method of streaming a plurality of messages from a source queue to at least one destination queue over a computer network. The method may include steps of generating a remote procedure call, the remote procedure being configured to encapsulate at least header data, message data for each of the plurality of messages and an end of batch token, the header data being common to each of the plurality of messages and including an identification of the at least one destination queue, the end of batch token signaling that no further message data follows; sending the generated remote procedure call over the computer network to the destination queue identified in the header data, and dequeueing at least the message data for each of the plurality of messages from the source queue and streaming the dequeued messages over the network, and successively enqueueing each streamed message data into the at least one destination queue identified by the header data until the end of batch token is received.

Abstract: An approach migrates database sessions from a database server on which performance and resource availability requirements are not being met to another database server. Because workload is removed from the database server not meeting these requirements, improved performance there is promoted. Furthermore, the approach switches the users in a way that attempts to keep performance and resource availability levels at the database server receiving the database sessions within goals for performance and resource availability.

Abstract: Approaches are used for efficiently and effectively managing the dynamic allocation of resources of multi-node database systems between services provided by the multi-node database server. A service is a category of work that is hosted on the database server. The approaches manage allocation of resources at different levels. For services that use a particular database, the performance realized by the services is monitored. Resources assigned to the database are allocated between these services to ensure performance goals for each are met. Resources assigned to a cluster of nodes are allocated between the databases to ensure that performance goals for all the services that use the databases are met. Resources assigned to a farm of clusters are assigned amongst clusters based on service level agreements and back-end policies. The approach uses a hierarchy of directors to manage resources at the different levels.

Abstract: Techniques are provided for creating dynamic connections to objects on remote database clusters. Service-to-instance mapping information is provided to a listener process for a cluster database. The service-to-instance mapping indicates the current provider instance(s) of each object within the cluster database. To establish a connection to a remote object, a sending process uses an object link. The object link identifies the desired destination object, but not the provider instance of the object. The object link also contains a authentication information and other connection information that exists in regular database links. The global listener for the cluster database uses the service-to-instance mapping to determine which instance is the current provider of the specified object, and dynamically distinguishes the appropriate database instance as the endpoint of the connection.

Abstract: A method and mechanism for dynamically changing the logical path of a state machine to avoid conflicts or problems is provided. A toggle state is employed for a state machine that allows dynamic changes in the computation path of a state machine. By analyzing the expected response state of a remote state machine, toggle states can be inserted in the path of a local state machine to avoid conflicts. This approach can be advantageously employed to reduce or prevent half-duplex violations for communications between applications on multiple computing nodes.

Abstract: An approach efficiently and dynamically allocates and de-allocates database instances and nodes between databases. The approach performs this function in a way that accounts for the users of and services hosted by multiple databases.

Abstract: An approach efficiently and dynamically places services within a multi-node system when expanding or contracting services, that is, increasing and decreasing the number of instances that host a service. Service placement decisions are made in a way that accounts for performance and availability requirements of both the service being placed and other services.

Abstract: An approach generates performance grades. A performance grade is a value or set of values that indicates the relative work performance offered by a resource, such as a server in a multi-node system, relative to other resources. Performance grades are used to dynamically allocate work within a multi-node computer system. For example, performance grades are used for connection-time balancing, and to direct a database connection request to a multi-node database instance that a performance grade indicates provides better performance. Performance grade deltas are generated that reflect the incremental change in performance grade for additional sessions or work. Performance deltas are used to direct incoming sessions, to more optimally balance workload, and to deal with logon storms where a large number of connect requests arrive in a very short time period.

Abstract: A server side connection pool provides pooling of server connections. Thus, client side processes do not create groups of dedicated resources. Clients are provided the capability to communicate to a server side connection broker process to GET a pooled server connection comprising connection state plus a thread of execution for doing some work, whereby requesting the work can bypass the connection broker process and go directly to the assigned pooled connection. Once the client issues a RELEASE to release the pooled connection back to the pool, a completely different client process on potentially a different client middle tier machine can reuse the same pooled connection. The server-side connection pool can be logically partitioned into sub-pools that correspond to connection classes that typically correspond to respective applications. A client process can request a pooled connection having a particular state, where a stored procedure can be executed to generate such state.

Abstract: An optimization of the two-phase commit protocol employed in distributed systems. Each cohort component of the distributed system augments messages that are accessible to the coordinator component with state information indicating whether the cohort is read-only with regard to a transaction that the coordinator is coordinating. The coordinator retains the most recent state information. The coordinator reads the retained state information for the cohorts and when the transaction terminates, the coordinator reads the retained state information. Where the cohort's state is read-only, the coordinator simply sends an abort message instead of performing the full two-phase commit protocol with regard to the read-only cohort. In the trees of distributed system components that are defined by transactions, any cohort which has children in the tree is a local coordinator for its children.

Abstract: A method and mechanism for reducing the expense of data transmissions and storage between a first node and a second for a remote-mapped query or a query involving a distributed join operation is disclosed. Data prefetching can be utilized to predictably retrieve information. Data redundancy management can be employed to reduce the expense of transmitting and storing redundant data.

Abstract: A system and method is disclosed that allows resources to be shared among multiple entities, but which can appropriately release system resources after the failure or shutdown of the calling entity. In one approach, a monitoring entity is available to check for session failures. If a session failure is detected, the session is identified in a shared list that is accessible to other related entities. The related entities can be configured to piggyback a message to an appropriate node to kill, shutdown, or release resources associated with the failed session. Alternatively, a related entity can be specifically initiated to send a message to the appropriate node to kill, shutdown, or release the resources.

Abstract: A method, system, and computer program product is disclosed for caching results in a client-side cache. Embodiments of a method, a system, and a computer program product are disclosed that associate a first snapshot of a database with a client that indicates a state of the database after a last database request by the client, and indicate any number of invalid cached results in the client cache for the client based upon the first snapshot. In some embodiments, the method further includes receiving a second snapshot that indicates a state of the database upon receipt of a database server request by the client, and updating the first snapshot with the second snapshot.

Abstract: A method, system, and computer program product is disclosed for interacting with a client supported by a client-side cache. Embodiments of a method, a system, and a computer program product are disclosed that retrieve a first snapshot, indicating a state of the database after a last database request by the client, associated with the client, determine any number of invalid cached results for the client based on the first snapshot, and transmit the any number of invalid cached results and a second snapshot, an update for the first snapshot.

Abstract: Described herein is a session reuse approach that reuses a session already established on a remote participant to execute an autonomous transaction. The session is reused in a manner that avoids affecting the session's state in a way adverse to later execution of the containing transaction. When beginning an autonomous transaction on a local participant, a request to initiate an autonomous transaction on a remote participant is deferred or not sent at all if the containing transaction is a distributed one. The request may be sent later, piggybacked to another message, using a piggyback messaging system. When ending an autonomous transaction, a local participant may send a request to a remote participant requesting that the remote participant commence execution of its respective containing transaction. The request is piggybacked to another message, and is thus transmitted without having to transmit the request separately, avoiding a message round trip.

Abstract: An improved method, mechanism, and system for implementing, generating, and maintaining for implementing session pools is disclosed. Disclosed is a method, mechanism, and system for dynamic sizing of session pools, in which the number of sessions in a given session pool or sub-session pool can be dynamically adjusted upwards or downwards. Also disclosed is an approach for customizing a session in a session pool with a specific set of affinities and attributes, in which tags can be associated with the customized sessions. Tagging can be used to identify sessions to deallocate/reallocate to dynamically size the session or sub-session pools.

Abstract: Disclosed are improved methods, systems, and mediums for implementing a dynamic cursor cache. Cached cursors are tagged to facilitate identification and reuse of cursors from a cursor cache. Cursor caches and cursor usage are managed in an integrated and/or coordinated manner between multiple nodes that have related sets of cursors or cursor resources.