Abstract: A target database is synchronized with a source database and the source database is replicated to the target database in a database replication system. The source database is on-line during the synchronization. The source database is located at a first node of the system, and the target database is located at a second node of the system. Changes in the source database are replicated to the target database by sending a replication stream from the first node to the second node. Successive blocks of data are sent from the first node to the target database to synchronize or resynchronize the target database with the source database. Each block of data includes one or more rows of data. The successively sent blocks of data are inserted into the replication stream at a point when the respective blocks of data are current or consistent in the source database, and the replication stream is posted to the target database. Synchronization or resynchronization thereby occurs simultaneously with replication.

Abstract: A target database is synchronized with a source database and the source database is replicated to the target database in a database replication system. The source database is on-line during the synchronization. The source database is located at a first node of the system, and the target database is located at a second node of the system. Changes in the source database are replicated to the target database by sending a replication stream from the first node to the second node. Successive blocks of data are sent from the first node to the target database to synchronize or resynchronize the target database with the source database. Each block of data includes one or more rows of data. The successively sent blocks of data define a loading stream. The successively sent blocks of data are posted into the target database when the replication stream is occurring slower than the loading stream. Synchronization or resynchronization thereby occurs simultaneously with replication.

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: 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: Collisions are resolved in a database replication system. The system includes a plurality of nodes arranged in either a master-slave or network configuration. Each node includes a database, wherein changes made at the databases of each node are replicated to the databases at one or more of the other nodes. When a collision is detected during data replication between multiple nodes, the collision is resolved by a rule that gives precedence to certain nodes over other nodes.

Abstract: A data replication engine is controlled in a system that replicates data associated with a plurality of transactions from a source database to a target database. The system includes a change queue that contains transaction data associated with the transactions. The system maintains one or more attributes outside of the change queue which are associated with transactions. One or more attributes outside of the change queue are identified which are associated with a transaction. The one or more of the identified attributes are then used to control the replication engine.

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.