Synchronization mechanism for serialized data log replay in database systems

Patent metadata

Field	Value
Publication number	US-10762107-B2
Application number	US-201715409234-A
Country	US
Kind code	B2
Filing date	Jan 18, 2017
Priority date	Nov 29, 2016
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

A computer implemented method for updating a secondary database includes receiving transaction log information from a primary database system at a secondary database system. The transaction log information comprises a first marker identifying a beginning of an operation comprising a plurality of sub-operations and a second marker identifying an end of the operation. The transaction log information is sequentially parsed, a first marker is identified, and a lock state is created after replaying the first marker to ensure proper serialization of the plurality of sub-operations. The lock state is terminated after replaying the second marker. Related apparatus, systems, techniques and articles are also described.

First claim

What is claimed is:

1. A computer implemented method comprising:
receiving transaction log information from a primary database system at a secondary database system, the transaction log information comprising a first marker identifying a beginning of an operation comprising a plurality of sub-operations and a second marker identifying an end of the operation;
parsing the transaction log information one operation at a time in an order operations appear in the transaction log; identifying the first marker; creating a lock state after replaying the first marker to ensure proper serialization of the plurality of sub-operations;
and terminating the lock state after replaying the second marker, wherein: the lock state locks tables on the secondary database system, the first marker is a Data Definition Language (Data Definition Language) Start (DDLStart) transaction log record and the second marker is a DDL End (DDLEnd) transaction log record;
and a DDL Operation Scope object on a DDL Operation thread stack controls writing of the DDLStart and DDLEnd transaction log records so that that the DDLEnd is always written regardless of how the DDL operation thread exits.

2. The method of claim 1 , wherein the transaction log information is parsed in a continuous replay context.

3. The method of claim 1 , wherein the primary database system and the secondary database system are configured to operate in a load balancing operation.

4. The method of claim 1 , wherein the secondary database actively responds to queries delegated to the secondary database system by the primary database system based on data contained in the main memory.

5. The method of claim 1 , wherein the secondary database system is configured as a back-up database system.

6. The method of claim 1 , wherein the transaction log information is generated by the primary database system based on queries received by the primary database system.

7. The method of claim 1 , wherein the operations are data definition language (DDL) queries.

8. The method of claim 1 , wherein the first marker and the second marker are inserted into the transaction log information by the primary database system.

9. The method of claim 1 , wherein the primary database system and the secondary database system are in memory database (IMDB) systems.

10. The method of claim 1 , wherein the primary database system and the secondary database system are column oriented database systems.

11. A system comprising:
a processor;
and a non-transitory computer readable media having computer executable instructions stored therein, which, when executed by the processor, causes the system to perform operations comprising: receiving transaction log information from a primary database system at a secondary database system, the transaction log information comprising a first marker identifying a beginning of an operation comprising a plurality of sub-operations and a second marker identifying an end of the operation;
parsing the transaction log information one operation at a time in an order operations appear in the transaction log; identifying the first marker; creating a lock state after replaying the first marker to ensure proper serialization of the plurality of sub-operations;
and terminating the lock state after replaying the second marker, wherein: the lock state locks tabes on the secondary database system, the first marker is a Data Definition Language (Data Definition Language) Start (DDLStart) transaction log record and the second marker is a DDL End (DDLEnd) transaction log record;
and a DDL Operation Scope object on a DDL Operation thread stack controls writing of the DDLStart and DDLEnd transaction log records so that that the DDLEnd is always written regardless of how the DDL operation thread exits.

12. The system of claim 11 , wherein the transaction log information is parsed in a continuous replay context.

13. The system of claim 11 , wherein the primary database system and the secondary database system are configured to operate in a load balancing operation.

14. The system of claim 11 , wherein the secondary database actively responds to queries delegated to the secondary database system by the primary database system based on data contained in the main memory.

15. The system of claim 11 , wherein the secondary database system is configured as a back-up database system.

16. The system of claim 11 , wherein the transaction log information is generated by the primary database system based on queries received by the primary database system.

17. The system of claim 11 , wherein the operations are data definition language (DDL) queries.

18. The system of claim 11 , wherein the first marker and the second marker are inserted into the transaction log information by the primary database system.

19. The system of claim 11 , wherein the primary database system and the secondary database system are in memory database (IMDB) systems.

20. The system of claim 11 , wherein the primary database system and the secondary database system are column oriented database systems.

Assignees

• Sap Se

Inventors

• Florendo Colin
• Gottipati Chaitanya
• Muehle Michael
• Basak Nirvik
• Andrei Mihnea
• Peh Thomas

Classifications

• G06F16/273 Primary

  Asynchronous replication or reconciliation · CPC title