Abstract: A database rollback processor allows rollback, or rewind, of the data and metadata to a point at which a failover or other metadata change occurred, therefore “rewinding” the metadata to a previous consistent point. The rollback processor identifies transaction entries in a redo log resulting in changes to the metadata. The changes are identified backward to a target recovery time. Transactions affecting the metadata are stored in a stack. The transactions are then backed out of the metadata according to the stack to restore the metadata to the state at the target recovery time. Data changes from the redo log may then be applied to the corresponding metadata as it existed at the target recovery time. Since the target recovery time is not bound by the timing of the snapshots, but rather may be at an arbitrary point chosen as the target recovery time, a failover, replication or recovery operation need not rely on the snapshot time.

Abstract: Computer-implemented methods and computer systems for automatically managing stored checkpoint data are described. The method includes accessing a first user defined time period. The first user defined time period is related to a plurality of stored checkpoint data, and each checkpoint data of the plurality of stored checkpoint data has an associated storage time. Further, the method includes identifying a first set of checkpoint data having storage times that are within the first user defined time period. Moreover, the method includes identifying a second set of checkpoint data having storage times that are older than the first user defined time period. In addition, the method includes pruning the second set of checkpoint data according to a user specified process in proportion to storage time of each checkpoint data of the second set of checkpoint data. The older stored checkpoint data is more heavily pruned over recent stored checkpoint data.

Abstract: A method and system that annotates a redo log to provide information concerning the execution of a procedure at a primary database. The annotations include entry and exit markers that indicate the beginning and the end of the execution along with any arguments passed to the procedure, and whether the execution of the procedure was successful. At the standby database, these markers are used to create a logical transaction associated with the procedure. The operations performed by the procedure are grouped into individual transactions, and these individual transactions are grouped as belonging to the logical transaction. If the execution of the procedure was successful at the primary database, then the individual transactions are discarded, and the logical transaction is applied by executing the procedure at the standby database. If the execution of the procedure failed at the primary database, then the individual transactions and the logical transaction are discarded.

Abstract: A method and system that annotates a redo log to provide information concerning the execution of a procedure at a primary database. The annotations include entry and exit markers that indicate the beginning and the end of the execution along with any arguments passed to the procedure, and whether the execution of the procedure was successful. At the standby database, these markers are used to create a logical transaction associated with the procedure. The operations performed by the procedure are grouped into individual transactions, and these individual transactions are grouped as belonging to the logical transaction. If the execution of the procedure was successful at the primary database, then the individual transactions are discarded, and the logical transaction is applied by executing the procedure at the standby database. If the execution of the procedure failed at the primary database, then the individual transactions and the logical transaction are discarded.

Abstract: Techniques for making light-weight checkpoints in logs of streams of transactions and for extending the logs from the checkpoints. The state saved in the light weight checkpoint need only include the state of all transactions that are active at a prior point in the log and are still active at the checkpoint. A log is extended from the checkpoint by processing new transactions in the transaction stream beginning at the prior point to produce the extending log. When the checkpoint is reached, the state saved at the checkpoint is used to continue to produce the extending log. Techniques are further disclosed for selecting points in the stream of transactions at which the checkpoints may be made and for determining the distance between checkpoints. As disclosed, the log in which the checkpoints are used is a logical log made from a physical log produced by a relational database system. The logical log may be used for replication and for data mining.

Abstract: A method and system that annotates a redo log to provide information concerning the execution of a procedure at a primary database. The annotations include entry and exit markers that indicate the beginning and the end of the execution along with any arguments passed to the procedure, and whether the execution of the procedure was successful. At the standby database, these markers are used to create a logical transaction associated with the procedure. The operations performed by the procedure are grouped into individual transactions, and these individual transactions are grouped as belonging to the logical transaction. If the execution of the procedure was successful at the primary database, then the individual transactions are discarded, and the logical transaction is applied by executing the procedure at the standby database. If the execution of the procedure failed at the primary database, then the individual transactions and the logical transaction are discarded.

Abstract: Techniques for making light-weight checkpoints in logs of streams of transactions and for extending the logs from the checkpoints. The state saved in the light weight checkpoint need only include the state of all transactions that are active at a prior point in the log and are still active at the checkpoint. A log is extended from the checkpoint by processing new transactions in the transaction stream beginning at the prior point to produce the extending log. When the checkpoint is reached, the state saved at the checkpoint is used to continue to produce the extending log. Techniques are further disclosed for selecting points in the stream of transactions at which the checkpoints may be made and for determining the distance between checkpoints. As disclosed, the log in which the checkpoints are used is a logical log made from a physical log produced by a relational database system. The logical log may be used for replication and for data mining.

Abstract: A method and system that annotates a redo log to provide information concerning the execution of a procedure at a primary database. The annotations include entry and exit markers that indicate the beginning and the end of the execution along with any arguments passed to the procedure, and whether the execution of the procedure was successful. At the standby database, these markers are used to create a logical transaction associated with the procedure. The operations performed by the procedure are grouped into individual transactions, and these individual transactions are grouped as belonging to the logical transaction. If the execution of the procedure was successful at the primary database, then the individual transactions are discarded, and the logical transaction is applied by executing the procedure at the standby database. If the execution of the procedure failed at the primary database, then the individual transactions and the logical transaction are discarded.

Abstract: A database rollback processor allows rollback, or rewind, of the data and metadata to a point at which a failover or other metadata change occurred, therefore “rewinding” the metadata to a previous consistent point. The rollback processor identifies transaction entries in a redo log resulting in changes to the metadata. The changes are identified backward to a target recovery time. Transactions affecting the metadata are stored in a stack. The transactions are then backed out of the metadata according to the stack to restore the metadata to the state at the target recovery time. Data changes from the redo log may then be applied to the corresponding metadata as it existed at the target recovery time. Since the target recovery time is not bound by the timing of the snapshots, but rather may be at an arbitrary point chosen as the target recovery time, a failover, replication or recovery operation need not rely on the snapshot time.

Abstract: Computer-implemented methods and computer systems for automatically managing stored checkpoint data are described. The method includes accessing a first user defined time period. The first user defined time period is related to a plurality of stored checkpoint data, and each checkpoint data of the plurality of stored checkpoint data has an associated storage time. Further, the method includes identifying a first set of checkpoint data having storage times that are within the first user defined time period. Moreover, the method includes identifying a second set of checkpoint data having storage times that are older than the first user defined time period. In addition, the method includes pruning the second set of checkpoint data according to a user specified process in proportion to storage time of each checkpoint data of the second set of checkpoint data. The older stored checkpoint data is more heavily pruned over recent stored checkpoint data.

Abstract: The present invention is a paging scheme that provides improved performance for various applications. In one embodiment of the present invention, a method of paging data comprises the steps of storing a plurality of pages of data in a main memory, determining that paging must occur, and paging out a page of data from the main memory based on the memory pressure of the page of data. The paging out step may comprise the steps of determining an amount of time a page is or will be in memory for each of the plurality of pages of data in the main memory and determining a memory pressure for each of the plurality of pages of data in the main memory.

Abstract: Techniques for making light-weight checkpoints in logs of streams of transactions and for extending the logs from the checkpoints. The state saved in the light weight checkpoint need only include the state of all transactions that are active at a prior point in the log and are still active at the checkpoint. A log is extended from the checkpoint by processing new transactions in the transaction stream beginning at the prior point to produce the extending log. When the checkpoint is reached, the state saved at the checkpoint is used to continue to produce the extending log. Techniques are further disclosed for selecting points in the stream of transactions at which the checkpoints may be made and for determining the distance between checkpoints. As disclosed, the log in which the checkpoints are used is a logical log made from a physical log produced by a relational database system. The logical log may be used for replication and for data mining.