Asynchronous data replication using an external buffer table

Patent metadata

Field	Value
Publication number	US-2016179918-A1
Application number	US-201414574845-A
Country	US
Kind code	A1
Filing date	Dec 18, 2014
Priority date	Dec 18, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

Embodiments of the present invention provide, systems, methods, and computer program products for asynchronously replicating data from source tables of a source computer system to target tables of a target computer system. Embodiments of the present invention implement an external buffer table (EBT) from which changed data statements can be selectively applied to target tables, which can reduce the number of statements applied to the target tables of the target computer system.

First claim

1 - 11 . (canceled)

12 . A computer program product for asynchronously replicating data, comprising:
one or more computer readable storage media and program instructions stored on the one or more computer readable storage media, the program instructions comprising: program instructions to receive from a source computer system one or more statements that describe data changes on one or more source tables of the source computer system to be replicated on one or more target tables of the target computer system; program instructions to apply the one or more statements to an external buffer table of the target computer system; and program instructions to selectively apply the one or more statements from the external buffer table to the one or more target tables to replicate the data changes on the one or more target tables.

13 . The computer program product of claim 12 , wherein the program instructions to selectively apply the one or more statements from the external buffer table to the one or more target tables to replicate the data changes on the one or more target tables, comprise:
program instructions to, responsive to receiving, at the target system, a query referencing one or more target tables, apply statements corresponding to the referenced one or more target tables from the external buffer table to the one or more referenced target tables.

14 . The computer program product of claim 13 , wherein the program instructions to apply statements corresponding to the referenced one or more target tables from the external buffer table to the one or more referenced target tables, comprise:
program instructions to replicate data changes described by the applied statements on the one or more referenced target tables; and program instructions to delete from the external buffer table the applied statements.

15 . The computer program product of claim 12 , wherein the program instructions to selectively apply the one or more statements from the external buffer table to the one or more target tables to replicate the data changes on the one or more target tables, comprise:
program instructions to, responsive to receiving, at the target system, a query referencing one or more target tables, select statements in the external buffer table that correspond to the referenced one or more target tables and have an insert operation; and program instructions to select entries in the one or more target tables that correspond to the referenced one or more target tables, except entries having a named target table and row identifier that match a named target table and row identifier of a statement in the external buffer table having a delete operation.

16 . The computer program product of claim 12 , wherein the program instructions to selectively apply the one or more statements from the external buffer table to the one or more target tables to replicate the data changes on the one or more target tables, comprise:
program instructions to, responsive to detecting that a size of the external buffer table has exceeded a specified threshold, apply statements from the external buffer table to one or more target tables.

17 . A computer system for asynchronously replicating data, comprising:
one or more computer processors; one or more computer readable storage media; program instructions stored on the one or more computer readable storage media for execution by at least one of the one or more processors, the program instructions comprising: program instructions to receive from a source computer system one or more statements that describe data changes on one or more source tables of the source computer system to be replicated on one or more target tables of the target computer system; program instructions to apply the one or more statements to an external buffer table of the target computer system; and program instructions to selectively apply the one or more statements from the external buffer table to the one or more target tables to replicate the data changes on the one or more target tables.

18 . The system of claim 17 , wherein the program instructions to selectively apply the one or more statements from the external buffer table to the one or more target tables to replicate the data changes on the one or more target tables, comprise:
program instructions to, responsive to receiving, at the target system, a query referencing one or more target tables, apply statements corresponding to the referenced one or more target tables from the external buffer table to the one or more referenced target tables.

19 . The system of claim 18 , wherein the program instructions to apply statements corresponding to the referenced one or more target tables from the external buffer table to the one or more referenced target tables, comprise:
program instructions to replicate data changes described by the applied statements on the one or more referenced target tables; and program instructions to delete from the external buffer table the applied statements.

20 . The system of claim 17 , wherein the program instructions to selectively apply the one or more statements from the external buffer table to the one or more target tables to replicate the data changes on the one or more target tables, comprise:
program instructions to, responsive to receiving, at the target system, a query referencing one or more target tables, select statements in the external buffer table that correspond to the referenced one or more target tables and have an insert operation; and program instructions to select entries in the one or more target tables that correspond to the referenced one or more target tables, except entries having a named target table and row identifier that match a named target table and row identifier of a statement in the external buffer table having a delete operation.

21 . The system of claim 17 , wherein the program instructions to selectively apply the one or more statements from the external buffer table to the one or more target tables to replicate the data changes on the one or more target tables, comprise:
program instructions to, responsive to detecting that a size of the external buffer table has exceeded a specified threshold, apply statements from the external buffer table to one or more target tables.

22 . A method for asynchronously replicating data, comprising:
asynchronously replicating data changes made on one or more source tables of a source computer system to one or more target tables of a target computer system, wherein at least a portion of the data changes are applied an external buffer table of the target computer system and are selectively applied from the external buffer table to one or more target tables of the target computer system.

23 . The method of claim 22 , further comprising:
responsive to receiving, at the target system, a query referencing one or more target tables, applying, by the target system, data changes corresponding to the referenced one or more target tables from the external buffer table to the one or more referenced target tables.

24 . The method of claim 22 , further comprising:
responsive to detecting that a size of the external buffer table has exceeded a specified threshold, applying, by the target system, data changes from the external buffer table to one or more target tables.

25 . The method of claim 22 , further comprising:
responsive to detecting an idle state of the target computer system, applying, by the target system, data changes from the external buffer table to one or more target tables.

Assignees

• IBM

Inventors

• Martin Daniel
• O'Quinn Christopher R G
• Spyker James D
• Yao Yongfeng

Classifications

• G06F16/273 Primary

  Asynchronous replication or reconciliation · CPC title

• G06F16/951

  Indexing; Web crawling techniques · CPC title

• G06F16/2455

  Query execution · CPC title

• G06F16/242

  Query formulation · CPC title

• G06F16/254

  Extract, transform and load [ETL] procedures, e.g. ETL data flows in data warehouses · CPC title