Abstract: Herein is high availability for online transaction processing with redundancy and redo for a federation of pluggable databases and container databases. In an embodiment of a federation of container database management systems that includes a first container database, first redo data of a first pluggable database in a second container database is obtained based on a database dictionary in the first container database. To the first pluggable database in the first container database, the first redo data of the first pluggable database in the second container database is applied. Based on the database dictionary in the first container database, second redo data of a second pluggable database in a third container database is obtained. To the second pluggable database in the first container database, without modifying content of the first pluggable database in the first container database, the second redo data of the second pluggable database in the third container database is applied.

Abstract: Embodiments allow a primary database system (“primary”) to automatically detect queries directed to the primary database that may be offloaded to a standby database system (“standby”), and then to automatically offload the offload-eligible queries to a standby. The primary identifies offload-eligible queries based on a record of up-to-date database objects within each standby that replicates the primary database. The record of up-to-date standby objects is updated based on heartbeat messages from each standby, and commit timestamps for transactions on the primary. Evaluation of whether a query is offload-eligible is triggered by one or more trigger conditions that include: inclusion of an offload optimizer hint in the query, an estimated run-time of the query, etc. Embodiments further allow an offloaded query over particular changed data in the primary database to access, on a standby database, uncommitted changes made to the particular data in the primary database.

Abstract: Disclosed are methods and apparatuses to provide a redo repeater that allows for no data loss protection without the performance impact to the primary database even when a significant geographical distance separates the primary and standby databases. The Repeater is a lightweight entity that receives redo from the primary database with the purpose of redistributing that redo throughout the primary/standby system configuration. The Repeater able to extend no data loss protection and switchover functionality to terminal standby databases even though the primary database does not need to have a direct connection with those destinations.

Abstract: Disclosed is a system, method, and computer program product that generates masked data from within a database infrastructure. Instead of requiring an external tool to generate masked data, a database generates masked data using its internal processing mechanisms.

Abstract: Embodiments allow a primary database system (“primary”) to automatically detect queries directed to the primary database that may be offloaded to a standby database system (“standby”), and then to automatically offload the offload-eligible queries to a standby. The primary identifies offload-eligible queries based on a record of up-to-date database objects within each standby that replicates the primary database. The record of up-to-date standby objects is updated based on heartbeat messages from each standby, and commit timestamps for transactions on the primary. Evaluation of whether a query is offload-eligible is triggered by one or more trigger conditions that include: inclusion of an offload optimizer hint in the query, an estimated run-time of the query, etc. Embodiments further allow an offloaded query over particular changed data in the primary database to access, on a standby database, uncommitted changes made to the particular data in the primary database.

Abstract: Disclosed are methods and apparatuses to provide a redo repeater that allows for no data loss protection without the performance impact to the primary database even when a significant geographical distance separates the primary and standby databases. The Repeater is a lightweight entity that receives redo from the primary database with the purpose of redistributing that redo throughout the primary/standby system configuration. The Repeater able to extend no data loss protection and switchover functionality to terminal standby databases even though the primary database does not need to have a direct connection with those destinations.

Abstract: Disclosed are methods and apparatuses to provide a redo repeater that allows for no data loss protection without the performance impact to the primary database even when a significant geographical distance separates the primary and standby databases. The Repeater is a lightweight entity that receives redo from the primary database with the purpose of redistributing that redo throughout the primary/standby system configuration. The Repeater able to extend no data loss protection and switchover functionality to terminal standby databases even though the primary database does not need to have a direct connection with those destinations.

Abstract: A method, system, and computer program product. The method for non-intrusive redeployment of a standby database facility comprises configuring a database system having a shared lock manager process to synchronize two or more concurrent access instances, then granting lock requests for access to a cache of database blocks. At some moment in time, the shared lock manager process may fail, and a monitor process detects the failure or other stoppage of the shared lock manager process. A new shared lock manager process and other processes are started, at least one of which serves for identifying the database blocks in the cache that have not yet been written to the database. The identified blocks are formed into a recovery set of redo operations. During this time, incoming requests for access to the cache of database blocks are briefly blocked, at least until the recovery set of redo operations has been formed.

Abstract: Disclosed are methods and apparatuses to provide a redo repeater that allows for no data loss protection without the performance impact to the primary database even when a significant geographical distance separates the primary and standby databases. The Repeater is a lightweight entity that receives redo from the primary database with the purpose of redistributing that redo throughout the primary/standby system configuration. The Repeater able to extend no data loss protection and switchover functionality to terminal standby databases even though the primary database does not need to have a direct connection with those destinations.

Abstract: Disclosed are methods and apparatuses to provide a redo repeater that allows for no data loss protection without the performance impact to the primary database even when a significant geographical distance separates the primary and standby databases. The Repeater is a lightweight entity that receives redo from the primary database with the purpose of redistributing that redo throughout the primary/standby system configuration. The Repeater able to extend no data loss protection and switchover functionality to terminal standby databases even though the primary database does not need to have a direct connection with those destinations.

Abstract: A method and apparatus for applying changes to a standby database in real-time. According to one aspect, a change is applied to data contained in a standby database. The standby database functions as a replica of a primary database. The primary database has a current online redo log file to which a particular redo block was written. According to one aspect, prior to the archiving of the current online redo log file, the particular redo block is received at a process associated with the standby database. A change indicated by the particular redo block is applied to the data contained in the standby database.

Abstract: A data recovery methodology with bound transaction data loss is described in which a database operator is allowed to set a bound that limits the number of transactions that can be lost. Transactions are placed in a buffer to be sent asynchronously to the standby system and synchronized based on the predetermined bound and on the number of transactions currently in the buffer.

Abstract: Techniques are provided for replicating data on computer systems, including database systems. The operations of a group of transactions are rearranged to be executed in another set of transactions. A transaction in the other set of transactions may be executed independently of the timing of the execution of any other transaction from the set, so long as the set is committed as a group.

Abstract: Techniques used in an automatic failover configuration having a primary database system, a standby database system, and an observer for preventing divergence among the primary and standby database systems while increasing the availability of the primary database system. In the automatic failover configuration, the primary database system remains available even in the absence of both the standby and the observer as long as the standby and the observer become absent sequentially. The failover configuration further permits automatic failover only when the observer is present and the standby and the primary are synchronized and inhibits state changes during failover. The database systems and the observer have copies of failover configuration state and the techniques include techniques for propagating the most recent version of the state among the databases and the observer and techniques for using carefully-ordered writes to ensure that state changes are propagated in a fashion which prevents divergence.

Abstract: Techniques used in an automatic failover configuration having a primary database system, a standby database system, and an observer for preventing divergence among the primary and standby database systems while increasing the availability of the primary database system. In the automatic failover configuration, the primary database system remains available even in the absence of both the standby and the observer as long as the standby and the observer become absent sequentially. The failover configuration further permits automatic failover only when the observer is present and the standby and the primary are synchronized and inhibits state changes during failover. The database systems and the observer have copies of failover configuration state and the techniques include techniques for propagating the most recent version of the state among the databases and the observer and techniques for using carefully-ordered writes to ensure that state changes are propagated in a fashion which prevents divergence.

Abstract: Systems, methods, and other embodiments associated with remote database maintenance using parallel file transfers are described. One exemplary system includes a processor configured to run a database management system (DBMS) that is in turn configured to manage a database (DB). The DBMS may maintain a database log file that stores information about changes to the database. The system may also include a connection logic for establishing data transfer connections between the computing system and a remote computing system storing the database replica. The system may also include a partition logic that separates the database log file into multiple portions and a distribution logic that provides the multiple file portions in parallel to the remote computing system through the multiple data transfer connections.

Abstract: A method and apparatus for applying changes to a standby database in real-time is provided. According to one aspect, a change is applied to data contained in a standby database. The standby database functions as a replica of a primary database. The primary database has a current online redo log file to which a particular redo block was written. According to one aspect, prior to the archiving of the current online redo log file, the particular redo block is received at a process associated with the standby database. A change indicated by the particular redo block is applied to the data contained in the standby database.

Abstract: A version control system is described for use in connection with a database management system to facilitate versioning of a database table, the system including a database table and a version control module. The database table comprises a plurality of records, each record including at least one data field for storing user data and at least some of the records including a version control field including version control information. The version control module is configured to, in response to a user query related to the database table and related to a version, generate an augmented query for processing by the data base management system, the augmented query relating to the user query and the version control information.

Abstract: A method and apparatus for buffering is provided. A set of buffers is maintained in an ordered list based on a profit value generated for each buffer. The profit value for a buffer reflects multiple access characteristics of the buffer. The list of buffers is partitioned into divisions referred to as buckets. Each bucket contains a set of buffers and is associated with a subrange of the fall range of profit values that may be generated. The bucket that covers the very top of the list is associated with highest profit value subrange, the bucket that covers the bottom of the list is associated with the lowest profit value subrange. When data is first placed in a buffer, the buffer's position within the buffer list is not immediately based on its profit value. Instead, an access history is first accumulated for the buffer and, once accumulated, the buffer's profit value earns the buffer's place in the list.