Ensuring consistent replication of updates in databases

Patent metadata

Field	Value
Publication number	US-10970266-B2
Application number	US-201715827296-A
Country	US
Kind code	B2
Filing date	Nov 30, 2017
Priority date	Nov 30, 2017
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A method includes reading, by a capture engine, log data. The log data can be synchronously hardware-replicated. The log data reflects that an update was started for a database of a first site. The capture engine corresponds to a capture engine of a second site. The method also includes identifying, by the capture engine, the update. The method also includes determining whether the update was committed to the database of the first site. The method also includes replicating, by an apply engine, the update to a database of the second site based on the determining. The update is replicated to the database of the second site based on a determination that the update was committed to the database of the first site. The committed update corresponds to a consistent replication of updates across two or more databases that reside in multiple database management systems.

First claim

What is claimed is:

1. A computer-implemented method, the method comprising:
reading, by a capture engine, log data, wherein the log data comprises a hardware-replicated set of log data, and the log data reflects that an update was started for a database of a first site, and wherein the capture engine corresponds to a capture engine of a second site, wherein the first site corresponds to an active site and the second site corresponds to a standby site;
identifying, by the capture engine, the update by identifying a recovery token that corresponds to the update;
determining whether the update was committed to the database of the first site, wherein the update uses a two-phase commit protocol process and the determination that the update was committed is determined based on detecting an end of the two-phase commit protocol process in the log data;
replicating, by an apply engine, the update to a database of the second site based on the determining, wherein the update is replicated to the database of the second site based on a determination that the update was committed to the database of the first site, and the committed update corresponds to a consistent replication of updates across two or more databases,
wherein replicating the update to the database of the second site corrects an inconsistency between the database of the first site and the database of the second site,
wherein the apply engine and the capture engine are part of a replication engine that is implemented at the standby site; and
communicating the identified recovery token to another replication engine.

2. The computer-implemented method of claim 1 , wherein the log data comprises logs for one or more unique databases that are managed by different database management systems.

3. The computer-implemented method of claim 1 , wherein the update for the database of the first site is performed by a global transaction.

4. A computer system comprising:
a memory; and
a processor system communicatively coupled to the memory;
the processor system configured to perform a method comprising:
reading log data, wherein the log data comprises a hardware-replicated set of log data, and the log data reflects that an update was started for a database of a first site, and wherein the processor system corresponds to a processor system of a second site, wherein the first site corresponds to an active site and the second site corresponds to a standby site;
identifying the update by identifying a recovery token that corresponds to the update;
determining whether the update was committed to the database of the first site, wherein the update uses a two-phase commit protocol process and the determination that the update was committed is determined based on detecting an end of the two-phase commit protocol process in the log data;
replicating the update to a database of the second site based on the determining, wherein the update is replicated to the database of the second site based on a determination that the update was committed to the database of the first site, and the committed update corresponds to a consistent replication of updates across two or more databases,
wherein replicating the update to the database of the second site corrects an inconsistency between the database of the first site and the database of the second site,
wherein the apply engine and the capture engine are part of a replication engine that is implemented at the standby site; and
communicating the identified recovery token to another replication engine.

5. The computer system of claim 4 , wherein the log data comprises logs for one or more unique databases that are managed by different database management systems.

6. The computer system of claim 4 , wherein the update for the database of the first site is performed by a global transaction.

7. A computer program product comprising:
a computer-readable storage medium having program instructions embodied therewith, wherein the computer-readable storage medium is not a transitory signal per se, the program instructions readable by a processor system to cause the processor system to perform a method comprising:
reading, by a capture engine, log data, wherein the log data comprises a hardware-replicated set of log data, and the log data reflects that an update was started for a database of a first site, and wherein the capture engine corresponds to a capture engine of a second site, wherein the first site corresponds to an active site and the second site corresponds to a standby site;
identifying, by the capture engine, the update by identifying a recovery token that corresponds to the update;
determining whether the update was committed to the database of the first site, wherein the update uses a two-phase commit protocol process and the determination that the update was committed is determined based on detecting an end of the two-phase commit protocol process in the log data;
replicating, by an apply engine, the update to a database of the second site based on the determining, wherein the update is replicated to the database of the second site based on a determination that the update was committed to the database of the first site, and the committed update corresponds to a consistent replication of updates across two or more databases,
wherein replicating the update to the database of the second site corrects an inconsistency between the database of the first site and the database of the second site,
wherein the apply engine and the capture engine are part of a replication engine that is implemented at the standby site; and
communicating the identified recovery token to another replication engine.

8. The computer program product of claim 7 , wherein the log data comprises logs for one or more unique databases that are managed by different database management systems.

Assignees

• IBM

Inventors

• Bourbonnais Serge
• Cadarette Paul
• Clitherow David A
• Fitzpatrick Michael G
• Mclean Pamela
• Petersen David
• Thompson John G
• Vance Gregory W

Classifications

• G06F16/2358

  Change logging, detection, and notification (replication G06F16/27) · CPC title

• G06F16/275

  Synchronous replication · CPC title

• G06F16/2308 Primary

  Concurrency control (transaction processing G06F9/466) · CPC title

• G06F16/2365

  Ensuring data consistency and integrity · CPC title