Gravic, Inc.

Intel Corporation

Rpx Corporation

Gravie, Inc.

Wilbur H Highleyman

Bruce D Holenstein

Paul J Holenstein

John R Hoffmann

Dylan R Holenstein

Gary E Strickler

Jonathan M Ziegler

William A Grimm

Methods are provided for preventing constraint violations at a target database by a database replication system. The database replication system replicates database transactions from a change log of a source database to the target database. Each source database and each target database have one or more tables, and at least one of the target database tables has one or more constraints. The database replication system replicates database transactions from a change log for the source database to the target database. Each of the source database tables has an associated change log disk cache. For each database transaction, a database change is detected to the at least one of the source database tables that potentially causes a constraint violation at the target database as a result of one or more of the target database tables having one or more constraints. An application call, or a programmatic call by a database management system, is then made when the database change is detected to flush to a change log disk contents of the associated change log disk cache for the at least one of the source database tables which has a change log disk cache that may flush to the change log disk in a misordered manner compared to change log disk cache flushes from at least one other source database table. The application call, or the programmatic call by the database management system, prevents the potential constraint violation at the target database by the database replication system.

Methods for preventing constraint violations at a target database by a database replication system where an application call, or a programmatic call by a database management system, forces a flush of a change log

A method and apparatus are provided for avoiding target database constraint violations in a database replication system. The database replication system includes a source database and a target database, wherein target database transactions automatically abort due to constraint violations. Each database has one or more tables and at least one of the target database tables has one or more constraints. The database replication system replicates source database transactions. For each target database transaction corresponding to a replicated source database transaction, changes made at the source database are replicated to the target database. When it is detected that a replicated change causes a constraint violation as a result of one or more of the target database tables having one or more constraints, the applying of the database change to the target database of the database change is deferred and the database change is posted to an electronic list. Replicated changes that do not cause a constraint violation are immediately applied to the target database. This process is repeated for all of the changes within the replicated source database transaction. The database changes on the electronic list are iterated through by applying the database changes on the electronic list that no longer cause a constraint violation to the target database and removing the applied database changes from the electronic list, and by deferring again the applying of the database changes on the electronic list that still cause a constraint violation and maintaining the deferred database changes on the electronic list. A commit is performed for the target database transaction corresponding to the replicated source database transaction when a commit operation is detected in the replicated source database transaction, and when no database changes remain on the electronic list for the replicated source database transaction. The deferring process avoids the target database transactions automatically aborting due to constraint violations.

Method and apparatus for resolving target database constraint violations in a database replication system where target database transactions are automatically aborted due to constraints violations

An automated method is provided for use when replacing a currently operating data replication engine in a first system with a new data replication engine in the first system in a bidirectional data replication environment. The currently operating data replication engine in the first system and the new data replication engine in the first system replicates first database transactions from an audit trail of a first database in the first system to a second database in a second system. The new data replication engine in the first system generating a list of active database transactions in the first system, and sends the list of active database transactions to the new data replication engine in the second system as a first token. The new data replication engine in the second system receives the first token, fetches a transaction event from an audit trail of second database, and replicates the fetched transaction event to the new data replication engine of the first system when the fetched transaction event does not match a transaction on the list in the first token. These steps are repeated during operation of the new data replication engine of the second system. The currently operating data replication engine in the first system is stopped from replicating first database transactions when all of the transactions on the list of active database transactions that were generated have been replicated to the second system.

Method for replacing a currently operating data replication engine in a bidirectional data replication environment without application downtime and while preserving target database consistency, and by using audit trail tokens that provide a list of active transactions

Source database precommitted transactions are resolved in a target database of a database replication system when selected source database precommitted transactions are subsequently aborted in the source database.

Method and apparatus for resolving source database precommitted transactions that are replicated to a target database of a database replication system

An automated method is provided for replacing a currently operating data replication engine with a new data replication engine. The currently operating data replication engine replicates source database transactions including any new source database transactions committed in an audit trail of the source database before the currently operating data replication engine stops replicating. All new source database transactions that the currently operating data replication engine has not completed replicating are joined. The currently operating data replication engine is stopped when all of the source database transactions that were not joined have completed replicating. All joined transactions are then voted to be committed and are replicated. The new data replication engine replicates all new source database transactions started after the currently operating data replication engine stops.

Method for replacing a currently operating data replication engine with a new data replication engine without application downtime and while preserving target database consistency, and by joining the source database transactions

Target database constraint violations are potentially resolved in a database replication system by replacing, converting, or removing deferred database changes.

Method and apparatus for potentially resolving target database constraint violations in a database replication system by replacing, converting or removing deferred database changes

An automated method is provided for replacing a currently operating data replication engine with a new data replication engine. The currently operating data replication engine replicates source database transactions including any new source database transactions committed in an audit trail of the source database before the currently operating data replication engine stops replicating. A list of active database transactions is generated and recorded as a first token in the audit trail. The currently operating data replication engine is stopped when all of the database transactions in the first token have completed. The new data replication engine is started and positioned to begin processing source database transactions in the audit trail of the source database at a beginning position that is located at or prior to the position of the first token in the audit trail. The new data replication engine replicates source database transactions by ignoring source database transactions listed in the first token and those which completed prior to the position where the currently operating data replication engine stopped, and replicates remaining source database transactions started prior to the current engine stopping, plus those new database transactions started after the currently operating data replication engine stopped.

Method for replacing a currently operating data replication engine with a new data replication engine without application downtime and while preserving target database consistency, and by using audit trail tokens

A system and method of backing up an online database to a storage device is provided wherein the online database is actively changed by one or more applications. The backed up online database is then subsequently restored. The online database is backed up by copying the online database to the storage device, and during the copying of the online database, writing changes that are made to the online database to a change log for the portion of the online database that has already been copied to the storage device, and not writing changes that are made to the online database to the change log for the portion of the online database that has not yet been copied to the storage device. The changes in the change log are applied to the storage device by rolling the change log backwards, and applying only the most recent change contained in the change log for each data item in the storage device. The backed up online database is restored by loading the copied plurality of records in the online database from the storage device to a target database.

Method and system for implementing current, consistent, and complete backup copy by rolling a change log backwards against a storage device

A system and method of backing up an online database to a storage device is provided wherein the online database is actively changed by one or more applications. The backed up online database is then subsequently restored. The online database is backed up by copying the online database to the storage device, and during the copying of the online database, writing changes that are made to the online database to a change log for the portion of the online database that has already been copied to the storage device, and not writing changes that are made to the online database to the change log for the portion of the online database that has not yet been copied to the storage device. The online database is then restored by loading the backed up online database to a target database, and applying the changes in the change log to the target database by rolling the change log backwards, and applying only the most recent change contained in the change log for each data item in the target database.

Method and system for implementing current, consistent, and complete backups by rolling a change log backwards

An extractor and an applier of a database replication system are configured to perform the functions of resolving target database constraint violations for replicated database transactions. The extractor replicates changes made at the source database to the target database. An applier immediately applies the changes to the target database that do not cause a constraint violation. The applier also performs the remaining functions, including detecting database changes that cause constraint violations, subsequent processing of these detected database changes, and performing a commit for the database transaction when the constraint violations are resolved.

Method and apparatus for resolving target database constraint violations in a database replication system

A system and method of backing up an online database to a storage device is provided wherein the online database is actively changed by one or more applications. The backed up online database is then subsequently restored. The online database is backed up by copying the online database to the storage device, and during the copying of the online database, writing changes that are made to the online database to a change log for the portion of the online database that has already been copied to the storage device, and not writing changes that are made to the online database to the change log for the portion of the online database that has not yet been copied to the storage device. The online database is then restored by loading the backed up online database to a restore database, and applying the changes in the change log to the restore database.

Method and system for implementing current, consistent, and complete backups

A system is configured to ensure transactional integrity thereof. The system includes a first subsystem and a second subsystem. Each of the subsystems receive the same request to process a transaction. An indicia engine at each subsystem computes indicia of the outcome of the processing of the same request. The computed indicia from each of the subsystems is compared. An action is completed at one of the subsystems when the computed indicia does not match. The action completed at one of the subsystems is one or more of issuing a database rollback on one of the subsystems, executing self-diagnostics on one of the subsystems, shutting down one of the subsystems, taking one of the subsystems offline, aborting the transaction executing on one of the subsystems, and generating an error indication for one of the subsystems.

System for ensuring transactional integrity thereof that includes a plurality of subsystems, one of which takes an action upon a loss of transactional integrity

An automated method and computer program product are provided for synchronizing a column-oriented target database with a row-oriented source database. Change data are replicated from a change log of the row-oriented source database via a staging database to the column-oriented target database. The change data including inserts and deletes. Change data of the change log is read into the staging database and is consolidated and grouped into a consolidated grouping of inserts, and a consolidated grouping of deletes. The consolidated grouping of inserts from the staging database are applied to the target database in a batched manner, and the consolidated grouping of deletes from the staging database are applied to the target database in a batched manner.

Method and computer program product for efficiently loading and synchronizing column-oriented databases

An automated method is provided for replacing a currently operating data replication engine with a new data replication engine. A currently operating data replication engine reports its audit trail position upon stopping. The new data replication engine starts and is positioned at an audit trail position which is prior to the reported stopped audit trail position by an amount of the audit trail which corresponds to time that is equal to or greater than a source database transaction abort timer. The position of the new data replication engine to the stopped audit trail position defines a position window. Audit trail transactions are processed in the position window by the new data replication engine by ignoring transactions which committed or aborted in the position window, and replicating remaining transactions in the position window from the source database to the target database. The new data replication engine replicates all transactions that are started after the stopped audit trail position.

Method for replacing a currently operating data replication engine with a new data replication engine without application downtime and while preserving target database consistency

A method is provided for ensuring transactional integrity of a system that includes a first subsystem and a second subsystem. Each of the subsystems receive the same request to process a transaction. An indicia engine at each subsystem computes indicia of the outcome of the processing of the same request. The computed indicia from each of the subsystems is compared. An action is completed at one of the subsystems when the computed indicia does not match. The action completed at one of the subsystems is one or more of issuing a database rollback on one of the subsystems, executing self-diagnostics on one of the subsystems, shutting down one of the subsystems, taking one of the subsystems offline, aborting the transaction executing on one of the subsystems, and generating an error indication for one of the subsystems.

Method of ensuring transactional integrity of a system that includes a plurality of subsystems, one of which takes an action upon a loss of transactional integrity

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Blairstown, NJ, United States of America

Wilbur H Highleyman