Oracle International Corporation

Other

Douglas Andrew Voss

Joydip Kundu

Raymond Guzman

Stephen John Vivian

George H Claborn

Benedicto Elmo Garin, Jr

Qinqin Wang

Goutam Kulkarni

Archie Williams Brown

Mahesh Baburao Girkar

Roger MacNicol

Steve Lee

Jiangbin Luo

Anthony Adams

Benedito Elmo Garin, Jr

George Eadon

Parthasarathy Elangadu Raghunathan

Robert McGuirk

Robert R McGulrk

Systems for high-performance, low-latency database log mining applications. A method commences upon receiving a log mining query. The query specifies desired results that correspond to a prior logical state of the database system. A first type of processing entity is invoked to process contents of the redo stream by loading metadata into a data dictionary, and a second type of processing entity is invoked to construct metadata from the redo stream, wherein the constructed metadata pertains only database objects referenced in the query. During the time that the first type of processing entity is processing contents of the redo stream by loading metadata into a data dictionary, a process of a second type serves incoming queries using a subset of entries in the redo stream. When the data dictionary is completed, a switchover point is reached and thenceforth, incoming queries are served using the first type of processing entity.

Low latency query processing over a series of redo records

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.

Method and apparatus for data rollback

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.

Techniques for the log-based replication of high-level procedures

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.

Automatic failover configuration with lightweight observer

Techniques for the logical replication of high-level procedures

Automatic failover configuration with redundant abservers

Database system configured for automatic failover with no data loss

A system for enabling a user of a relational database to define and enforce ordered check constraints to insure that defined logical relationships are maintained between data values in pairs of adjacent rows when adjacency is defined by some ordering of the data. These inter-row conditions, here called 'ordered check constraints,' are expressed by a logical expressions which define a required relationship between the attributes of a given row and its adjacent row or rows. Arbitrarily complex expressions involving these sets of attributes can be formed to model the constraints of interest. These expressions can be created by the database in support of, for example, traditional primary key or uniqueness constraints, or they can be provided by the database user to model new more complex constraints such as a requirement that there be no gaps in a list of serial numbers. These constraints can then be efficiently supported in the presence of a b-tree or another ordered index structure by identifying any inserted, updated or deleted rows and evaluating the expression in the context of those rows and any associated adjacent rows. This approach is similar to that typically used in existing database systems to support primary key and uniqueness constraints, providing the user with the ability to model a much richer set of constraints using a generalized expression which extends and enhances the functionality of check constraints to permit relationships of data in different rows to be defined and enforced.

Generalized method for modeling complex ordered check constraints in a relational database system

A method, system, and computer program product provides a data dictionary that can represent multiple versions of the schema objects, and which provides improved performance, reduced computing costs, and more accurate results in a variety of applications, such as in a database redo log mining system. A method of providing a data dictionary comprises the steps of determining whether information about the data object is present in a denormalized data dictionary history table, and if the information about the data object is not present in the denormalized data dictionary history table, then querying a normalized data dictionary to obtain the information about the data object, including a version identifier of the data object, and storing the version identifier and the obtained information about the data object including the version identifier in the denormalized data dictionary history table.

On-demand multi-version denormalized data dictionary to support log-based applications

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Nashua, NH, United States of America

Douglas Andrew Voss