Method, server, and computer readable medium for index recovery using index redo log

Patent metadata

Field	Value
Publication number	US-11003540-B2
Application number	US-201916577604-A
Country	US
Kind code	B2
Filing date	Sep 20, 2019
Priority date	Sep 19, 2019
Publication date	May 11, 2021
Grant date	May 11, 2021

Abstract

The method is an index redo logging method performed by a database server. The method may include performing a first recovery step of determining, by an instruction for recovering via an index redo log comprising an index physical redo log and an index logical redo log, an index tree structure by applying the index physical redo log, wherein the index physical redo log is generated by first index redo logging corresponding to a change of the index tree structure; and performing a second recovery step of performing an index tree search on the determined index tree structure to obtain physical information of the index logical redo log, and applying the index logical redo log to the determined index tree structure using the obtained physical information, wherein the index logical redo log is generated by second index redo logging corresponding to a data change in the index or generated based on a table redo log by the instruction for recovering.

First claim

What is claimed is:

1. A method for recovery of an index performed by a database server, comprising:
performing a first recovery step of determining, by an instruction for recovering via an index redo log comprising an index physical redo log and an index logical redo log, an index tree structure by applying the index physical redo log, wherein the index physical redo log is generated by first index redo logging corresponding to a change of the index tree structure;
performing a second recovery step of performing an index tree search on the determined index tree structure to obtain physical information of the index logical redo log, and applying the index logical redo log to the determined index tree structure using the obtained physical information, wherein the index logical redo log is generated by second index redo logging corresponding to a data change in the index or generated based on a table redo log by the instruction for recovering.

2. The method of claim 1 , wherein the index logical redo log is generated by excluding at least the physical information among indexing instruction information for a transaction during the second index redo logging.

3. The method of claim 1 , wherein the index logical redo log is generated using operation information and data value information included in the table redo log when the index logical redo log is generated by the instruction for recovering.

4. The method of claim 1 , wherein the index physical redo log and the index logical redo log are distinguished by a presence or absence of the physical information.

5. The method of claim 1 , wherein the index physical redo log includes index structure change information corresponding to an index split operation or an index coalesce operation.

6. The method of claim 5 , wherein the index structure change information includes data information that a node has, wherein the node is added or deleted by changing the index tree structure.

7. The method of claim 1 , wherein the index logical redo log includes index data change information corresponding to an operation of inserting, deleting, or changing data in the index.

8. The method of claim 1 , wherein the index physical redo log includes at least one of physical information, target index information, operation information, or index data value information, and
wherein the index logical redo log includes at least one of target index information, operation information, or index data value information.

9. The method of claim 1 , wherein a generation time of the index logical redo log is variable before or after an occurrence time of the instruction for recovering.

10. A database server for performing a method for recovery of an index, comprising:
a processor; and
a storage unit,
wherein the processor performs:
a first recovery step of determining, by an instruction for recovering via an index redo log comprising an index physical redo log and an index logical redo log, an index tree structure by applying the index physical redo log, wherein the index physical redo log is generated by first index redo logging corresponding to a change of the index tree structure;
a second recovery step of performing an index tree search on the determined index tree structure to obtain physical information of the index logical redo log, and applying the index logical redo log to the determined index tree structure using the obtained physical information, wherein the index logical redo log is generated by second index redo logging corresponding to a data change in the index or generated based on a table redo log by the instruction for recovering.

11. The database server of claim 10 , wherein the index logical redo log is generated by excluding at least the physical information among indexing instruction information for a transaction during the second index redo logging.

12. The database server of claim 10 , wherein the processor generates the index logical redo log using operation information and data value information included in the table redo log when the index logical redo log is generated by the instruction for recovering.

13. The database server of claim 10 , wherein the index physical redo log and the index logical redo log are distinguished by the presence or absence of the physical information.

14. The database server of claim 10 , wherein the index physical redo log includes index structure change information corresponding to an index split operation or an index coalesce operation.

15. The database server of claim 14 , wherein the index structure change information includes data information of a node which is added or deleted by changing the index tree structure.

16. The database server of claim 10 , wherein the index logical redo log includes index data change information corresponding to an operation of inserting, deleting, or changing data in the index.

17. The database server of claim 10 , wherein the index physical redo log includes at least one of physical information, target index information, operation information, or index data value information, and
wherein the index logical redo log includes at least one of target index information, operation information, or index data value information.

18. The database server of claim 10 , wherein a generation time of the index logical redo log is variable before or after an occurrence time of the instruction for recovering.

19. A non-transitory computer readable medium having recorded thereon a program executable by a processor to perform a method for recovery of an index, the method comprising:
performing a first recovery step of determining, by an instruction for recovering via an index redo log comprising an index physical redo log and an index logical redo log, an index tree structure by applying the index physical redo log, wherein the index physical redo log is generated by first index redo logging corresponding to a change of the index tree structure;
performing a second recovery step of performing an index tree search on the determined index tree structure to obtain physical information of the index logical redo log, and applying the index logical redo log to the determined index tree structure using the obtained physical information, wherein the index logical redo log is generated by second index redo logging corresponding to a data change in the index or generated based on a table redo log by the instruction for recovering.

Assignees

• Tmaxdata Co Ltd
• Tmax Data Co Ltd

Inventors

• Park Sang Young
• Kim Taikyoung
• Lee Hakyong
• Oh Jaemin
• Cho Jaehyeong

Classifications

• G06F11/1469 Primary

  Backup restoration techniques · CPC title

• G06F11/1451

  by selection of backup contents · CPC title

• G06F11/1471 Primary

  involving logging of persistent data for recovery · CPC title

• G06F16/2272

  Management thereof · CPC title

• G06F16/1734

  Details of monitoring file system events, e.g. by the use of hooks, filter drivers, logs · CPC title