Method and apparatus for processing write-ahead log

Patent metadata

Field	Value
Publication number	US-11526495-B2
Application number	US-202016909429-A
Country	US
Kind code	B2
Filing date	Jun 23, 2020
Priority date	Dec 29, 2017
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A method and apparatus for processing a write-ahead log (WAL) in a storage device that records a WAL set key-value pair and a status key-value pair include determining a status of the WAL set key-value pair based on the status key-value pair, replaying all uncompleted WALs in the WAL set key-value pair when the status of the WAL set key-value pair is in a sealed state, modifying, in the status key-value pair, the status of the WAL set key-value from the sealed state to a completed state, and deleting the WAL set key-value pair in the completed state.

First claim

What is claimed is:

1. A method for processing a write-ahead log (WAL) in a storage device, wherein the method comprises:
recording a WAL set key-value pair and a status key-value pair, wherein the status key-value pair records a status of a plurality of WAL set key-value pairs such that WAL set key-value pairs in different statuses can be directly searched by querying the status key-value pair, and wherein the status comprises a sealed state, a complete state, a working state, or a deleted state;
replaying all uncompleted WALs in the WAL set key-value pair when the status of the WAL set key-value pair is in the sealed state, wherein the WAL set key-value pair in the sealed state is forbidden to record a new WAL, and wherein the WAL set key-value pair records a plurality of WALs;
modifying, in the status key-value pair, the status of the WAL set key-value pair from the sealed state to the completed state; and
deleting the WAL set key-value pair in the completed state.

2. The method of claim 1 , wherein a value of the status key-value pair comprises a key of the WAL set key-value pair and the status of the WAL set key-value pair corresponding to the key of the WAL set key-value pair.

3. The method of claim 1 , further comprising storing a first cursor key-value pair, wherein the status of the WAL set key-value pair recorded in the status key-value pair corresponding to the first cursor key-value pair comprises the sealed state.

4. The method of claim 1 , further comprising storing a second cursor key-value pair, wherein the status of the WAL set key-value pair recorded in the status key-value pair corresponding to the second cursor key-value pair comprises the completed state.

5. The method of claim 1 , wherein the WAL set key-value pair in the working state records a new WAL.

6. The method of claim 5 , wherein a quantity of WALs stored in the WAL set key-value pair in the working state is less than a maximum quantity of WALs.

7. The method of claim 1 , wherein a quantity of WALs stored in the WAL set key-value pair in the sealed state is equal to a maximum quantity of WALs.

8. An apparatus for processing a write-ahead log (WAL) in a storage device, wherein the apparatus comprises:
a memory configured to store instructions; and
a processor coupled to the memory, wherein the instructions cause the processor to be configured to:
record a WAL set key-value pair and a status key-value pair, wherein the status key-value pair records a status of a plurality of WAL set key-value pairs such that WAL set key-value pairs in different statuses can be directly searched by querying the status key-value pair, and wherein the status comprises a sealed state, a complete state, a working state, or a deleted state;
replay all uncompleted WALs in the WAL set key-value pair when the status of the WAL set key-value pair is in the sealed state, wherein the WAL set key-value pair in the sealed state is forbidden to record a new WAL, and wherein the WAL set key-value pair records a plurality of WALs;
modify, in the status key-value pair, the status of the WAL set key-value from the sealed state to the completed state; and
delete the WAL set key-value pair in the completed state.

9. The apparatus of claim 8 , wherein a value of the status key-value pair comprises a key of the WAL set key-value pair and the status of the WAL set key-value pair corresponding to the key of the WAL set key-value pair.

10. The apparatus of claim 8 , wherein the instructions further cause the processor to be configured to store a first cursor key-value pair, and wherein the status of the WAL set key-value pair recorded in the status key-value pair corresponding to the first cursor key-value pair comprises the sealed state.

11. The apparatus of claim 8 , wherein the instructions further cause the processor to be configured to store a second cursor key-value pair, and wherein the status of the WAL set key-value pair recorded in the status key-value pair corresponding to the second cursor key-value pair comprises the completed state.

12. The apparatus of claim 8 , wherein the WAL set key-value pair in the working state records a new WAL.

13. The apparatus of claim 12 , wherein a quantity of WALs stored in the WAL set key-value pair in the working state is less than a maximum quantity of WALs.

14. The apparatus of claim 8 , wherein a quantity of WALs stored in the WAL set key-value pair in the sealed state is equal to a maximum quantity of WALs.

15. A computer program product comprising a non-transitory computer-readable storage medium having computer-executable instructions for processing a write-ahead log (WAL) in a storage device, wherein the computer-executable instructions, when executed by a processor, cause a computer to:
record a WAL set key-value pair and a status key-value pair, wherein the status key-value pair records a status of a plurality of WAL set key-value pairs such that WAL set key-value pairs in different statuses can be directly searched by querying the status key-value pair, and wherein the status comprises a sealed state, a complete state, a working state, or a deleted state;
replay all uncompleted WALs in the WAL set key-value pair when the status of the WAL set key-value pair is in the sealed state, wherein the WAL set key-value pair in the sealed state is forbidden to record a new WAL, and wherein the WAL set key-value pair records a plurality of WALs;
modify, in the status key-value pair, the status of the WAL set key-value from the sealed state to the completed state; and
delete the WAL set key-value pair in the completed state.

16. The computer program product of claim 15 , wherein a value of the status key-value pair comprises a key of the WAL set key-value pair and the status of the WAL set key-value pair corresponding to the key of the WAL set key-value pair.

17. The computer program product of claim 15 , wherein the computer-executable instructions further cause the computer to be configured to store a first cursor key-value pair, and wherein the status of the WAL set key-value pair recorded in the status key-value pair corresponding to the first cursor key-value pair comprises the sealed state.

18. The computer program product of claim 15 , wherein the computer-executable instructions further cause the computer to be configured to store a second cursor key-value pair, and wherein the status of the WAL set key-value pair recorded in the status key-value pair corresponding to the second cursor key-value pair comprises the completed state.

19. The computer program product of claim 15 , wherein the WAL set key-value pair in the working state records a new WAL, and wherein a quantity of WALs stored in the WAL set key-value pair in the working state is less than a maximum quantity of WALs.

20. The computer program product of claim 15 , wherein a quantity of WALs stored in the WAL set key-value pair in the sealed state is equal to a maximum quantity of WALs.

Assignees

• Huawei Tech Co Ltd

Inventors

• Yan Xiaolin

Classifications

• G06F16/2365 Primary

  Ensuring data consistency and integrity · CPC title

• G06F16/28

  Databases characterised by their database models, e.g. relational or object models · CPC title

• G06F16/2379 Primary

  Updates performed during online database operations; commit processing · CPC title

• G06F16/2246

  Trees, e.g. B+trees · CPC title