Abstract: A method of performing transactions in accordance with fairness criteria is provided wherein one of a plurality of entities initiates a transaction on an object at a database. The steps or operations of the initiated transaction are immediately processed up to the transaction ownership step. Propagation delays are determined between the database and at least some of the other entities that are capable of initiating transactions to the database. The propagation delays and a fairness criteria is used to determine the fair propagation delay period. Upon determining that the fair propagation delay period has been exceeded, it is detecting whether any of the other entities initiated a transaction on the same object during the fair propagation delay time period. If not, then the transaction initiating entity performs the transaction ownership step on the initiated transaction.

Abstract: A method is provided for replicating transaction data from a source database to a target database wherein the transaction data is communicated from a change queue associated with the source database to the target database. An initial path is provided between the change queue and the target database for transaction data to flow. The initial path has a maximum transaction load capacity. It is then detected whether the current transaction load is close or equal to the maximum transaction load capacity of the initial path. If so, another path is provided between the change queue and the target database.

Abstract: A method is provided for replicating transaction data from a source database to a target database wherein the transaction data is communicated from a change queue associated with the source database to the target database. An initial path is provided between the change queue and the target database for transaction data to flow. The initial path has a maximum transaction load capacity. It is then detected whether the current transaction load is close or equal to the maximum transaction load capacity of the initial path. If so, another path is provided between the change queue and the target database.

Abstract: A method is provided for replicating transaction data from a source database to a target database wherein the transaction data is communicated from a change queue associated with the source database to the target database. An initial path is provided between the change queue and the target database for transaction data to flow. The initial path has a maximum transaction load capacity. It is then detected whether the current transaction load is close or equal to the maximum transaction load capacity of the initial path. If so, another path is provided between the change queue and the target database. Also, a method is provided of replicating transaction data from a source database to a target database wherein an associated with the target database has a maximum transaction threshold limit. The applier normally posts transaction data to the target database only upon receipt of a commit step or operation associated with respective transaction data.

Abstract: An automated method is provided of replicating a locking protocol in a database environment for performing I/O operations wherein the database environment includes a plurality of databases. A locking protocol is performed that includes one or more explicit locking operations on objects in a first database of the database environment. The one or more explicit locking operations are replicated in one or more other databases in the database environment. At least some of the explicit locking operations are performed asynchronously with respect to the explicit locking operations performed in the first database. I/O operations are performed at the first database of the database environment that are associated with the one or more explicit locking operations implemented in the first database.

Abstract: A method is provided for loading data from a source database to a target database that includes at least one table. Prior to loading the data from the source database into the target database, at least one referential integrity constraint and/or at least one consistency requirement regarding the data is automatically identified. A subset of the data that satisfies the at least one referential integrity constraint and/or consistency requirement is then automatically identified. The identified subset of the data is then loaded into the target database as a unit of work.

Abstract: A method is provided for replicating transaction data from a source database to a target database wherein the transaction data is communicated from a change queue associated with the source database to the target database. An initial path is provided between the change queue and the target database for transaction data to flow. The initial path has a maximum transaction load capacity. It is then detected whether the current transaction load is close or equal to the maximum transaction load capacity of the initial path. If so, another path is provided between the change queue and the target database. Also, a method is provided of replicating transaction data from a source database to a target database wherein an associated with the target database has a maximum transaction threshold limit. The applier normally posts transaction data to the target database only upon receipt of a commit step or operation associated with respective transaction data.

Abstract: A method is provided for processing base level data of a change queue that is not serialized at the logical level. The base level change queue data is transaction data previously posted to a source database. A logical replication engine is provided to replicate and post the change queue data to a target database in the order that the transaction data is stored in the change queue. Upon detection in the logical replication engine of change queue data that is not serialized at the logical level, the change queue data is reserialized at the logical level before the logical replication engine applies the change queue data to the target database. The change queue data that is not serialized at the logical level may be posted to the target database using asynchronous database access.

Abstract: During replication of transaction data from a source database to a target database via a change queue associated with the source database, one or more multiple paths are provided between the change queue and the target database. The one or more multiple paths cause at least some of the transaction data to become unserialized. At least some of the unserialized data is reserialized prior to or upon applying the originally unserialized transaction data to the target database. If the current transaction load is close or equal to the maximum transaction load capacity of a path between the change queue and the target database, another path is provided. If the maximum transaction threshold limit of an applier associated with the target database has been reached, open transactions may be prematurely committed.

Abstract: An automated method is provided of replicating a locking protocol in a database environment for performing I/O operations wherein the database environment includes a plurality of databases. A locking protocol is performed that includes one or more explicit locking operations on objects in a first database of the database environment. The one or more explicit locking operations are replicated in one or more other databases in the database environment. At least some of the explicit locking operations are performed asynchronously with respect to the explicit locking operations performed in the first database. I/O operations are performed at the first database of the database environment that are associated with the one or more explicit locking operations implemented in the first database.

Abstract: A method is provided for loading data from a source database to a target database that includes at least one table. Prior to loading the data from the source database into the target database, at least one referential integrity constraint and/or at least one consistency requirement regarding the data is automatically identified. A subset of the data that satisfies the at least one referential integrity constraint and/or consistency requirement is then automatically identified. The identified subset of the data is then loaded into the target database as a unit of work.

Abstract: Locks placed on corresponding objects held in a plurality of databases located at different nodes in a network during replication are released in accordance with fairness criteria. Propagation delays are determined between a transaction initiating node and one or more other nodes in the network. An object is locked during a transaction being executed at the transaction initiating node. Corresponding objects are locked at one or more other nodes in the network that are manipulated as a result of the replication Upon determining that the object locks should be released, the propagation delays are used to determine when to release the object locks so that all of the object locks at the one or more other nodes are released in accordance with the fairness criteria.

Abstract: Transactions are replicated from a source database to a target database in a data replication system. The system includes a first memory location that persistently stores statement text associated with transactions to be replicated. Transactions to be replicated are cached by separating the transactions into statement text and statement data. A determination is made as to whether the statement text has been previously stored in the first memory location. If not, then the statement text is persistently stored to the first memory location. A similar scheme is provided for replicating I/O operations.

Abstract: A method is provided of assigning processors in a multiprocessor environment to a plurality of processes that are executed in the multiprocessor environment. Each process has a process pair defined by a primary process that executes on a first processor, and a backup process that executes on a second processor. There are a plurality of process pairs. The processors are in communication with one another via a communication network. The processors are associated with a plurality of predefined processor pairs. First, a plurality of process pairs are provided that are initially assigned to a respective plurality of pairs of processors, wherein at least one of the processors in the plurality of pairs of processors is initially assigned to more than one processor pair. Each processor is then assigned to only one of the predefined processor pairs so that no processor belongs to more than one processor pair.

Abstract: A method is provided of assigning processors in a multiprocessor environment to a plurality of processes that are executed in the multiprocessor environment. Each process has a process pair defined by a primary process that executes on a first processor, and a backup process that executes on a second processor. There are a plurality of process pairs. The processors are in communication with one another via a communication network. The processors are associated with a plurality of predefined processor pairs. First, a plurality of process pairs are provided that are initially assigned to a respective plurality of pairs of processors, wherein at least one of the processors in the plurality of pairs of processors is initially assigned to more than one processor pair. Each processor is then assigned to only one of the predefined processor pairs so that no processor belongs to more than one processor pair.

Abstract: A split processing system is provided that has a plurality of nodes and a communication network. Each node includes one or more processors, or a processor subsystem including at least one processor and an operating system. Each node has a specific number of failure modes which is less than the number of failure modes in an unsplit system wherein all of the processors are located at a single node. The communication network allows the one or more processors at each of the nodes to interoperate with each other.

Abstract: Tokens are used to prepare a target database for replication from a source database and to confirm the preparation in an asynchronous coordinated commit replication process. During a dual write replication process, transmission of the replicated data and locking of data records in the target database occurs only on updates.

Abstract: A method is provided for splitting a system comprising a processor subsystem including a plural number (np) of processors, and an instance of a database. A number (nn) of nodes is selected that the system is to be split into. Each node may be provided with a processor subsystem including at least one processor. At least some of the nodes further include an instance of at least a portion of the database. A network is provided for communications among the nodes. At least some of the nodes that contain an instance of at least a portion of the database are automatically synchronized so that contents of the database that exist in plural nodes remain synchronized in at least some of the plural nodes whenever contents of the database at one of the nodes is changed. Systems with multiple processors, but without databases, may also be split in the same manner.

Abstract: Tokens are used to prepare a target database for replication from a source database and to confirm the preparation in an asynchronous coordinated commit replication process. During a dual write replication process, transmission of the replicated data and locking of data records in the target database occurs only on updates.

Abstract: A split processing system is provided that has a plurality of nodes and a communication network. Each node includes one or more processors, or a processor subsystem including at least one processor and an operating system. Each node has a specific number of failure modes which is less than the number of failure modes in an unsplit system wherein all of the processors are located at a single node. The communication network allows the one or more processors at each of the nodes to interoperate with each other.