International Business Machines Corporation

Tyrone Yu

Serge Bourbonnais

You-Chin Gene Fuh

James Z Teng

Austin F M D'Costa

Jonathan W Wierenga

Daniel B Morales

Clarence M Pruet

Techniques for restoring point-in-time and transaction consistency across consistency groups between a first and a second independent database management system (DBMS) for a disaster recovery. Several consistency groups (CGs) are defined for replication. For each CG in the first DBMS data changes are transmitted to a second DBMS. A timestamp representing a most recently received commit log record or a heartbeat during periods of inactivity for a CG is stored in a database table at regular intervals. At regular intervals, the timestamp is compared with timestamps for other CGs to identify a common time at which data to be applied to the CGs in the second DBMS have been received into a recoverable data store. The received data is applied to the CGs in the second DBMS up to the common time.

Restoring database consistency integrity

A system and method to ensure a low-latency read of log records from a Database Management System ('DBMS') in asynchronous log-based database replication capture from a blocking log read Application Programming Interface ('API'). The system may include a replication server with a log read module to initialize a log read thread. The reading module of the log read thread may read a predefined number of DBMS log records. A log flush module of the log flush thread may be executed by the log read thread and waits for a read complete notification. The update module, in response to a log flush thread time out, may also generate a plurality of loggable transactions such that a number of log records in an internal API log satisfies a DBMS threshold and unblocks the DBMS API. Therefore, the latency time may be constant, low, and predictable ensuring an accurate replication capture.

System and apparatus to ensure a low-latency read of log records from a database management system ('DBMS')

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San Jose, CA, United States of America

Tyrone Yu