Applying a database transaction log record directly to a database table container

Patent metadata

Field	Value
Publication number	US-9811549-B2
Application number	US-201414552914-A
Country	US
Kind code	B2
Filing date	Nov 25, 2014
Priority date	Nov 25, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Disclosed herein are system, method, and computer program product embodiments for directly restoring a database from a log volume. An embodiment operates by reading one or more database transaction log records from a log volume. The embodiment then loads from a database table persistent storage one or more pages containing rows in the database table that will be read from or written to by the one or more database transaction log records. The embodiment then loads a dictionary for each column associated with the one or more database transaction log records. The embodiment then applies the one or more database transaction log records directly into the one or more loaded pages and the one or more dictionaries. Each dictionary and page modified in memory is then written to the database table persistent storage when a savepoint operation is performed.

First claim

What is claimed is:

1. A computer implemented method for restoring a database from a log volume, comprising:
reading, by one or more computing devices, a log record from the log volume, wherein the log record includes information for restoring a database transaction that is not savepointed to a persistent storage;
interpreting, by the one or more computing devices, a page of a table in the database that is associated with the database transaction as a portion of an index vector that identifies one or more values in a column of the table, wherein the page is stored in the persistent storage;
performing, by the one or more computing devices, a direct modification of the portion of the index vector and a dictionary based on the log record, wherein the dictionary is associated with the index vector; and
applying, by the one or more computing devices, the database transaction to the database without replaying the log record as a query, wherein the applying comprises updating the table in the database on the persistent storage based on the modified portion of the index vector and the modified dictionary.

2. The method of claim 1 , further comprising:
identifying the page of the table in the database on the persistent storage, wherein the page is associated with the database transaction.

3. The method of claim 1 , the performing the direct modification comprising:
inserting a key in the portion of the index vector and the dictionary based on the database transaction; and
inserting a value in the dictionary based on the database transaction.

4. The method of claim 1 , the performing the direct modification comprising:
deleting a key in the portion of the index vector based on the database transaction.

5. The method of claim 1 , the performing the direct modification comprising:
altering a key in the portion of the index vector based on the database transaction.

6. The method of claim 1 , wherein the dictionary represents the one or more values in the column of the table.

7. A system, comprising:
a computer memory; and
at least one processor coupled to the memory and configured to:
read a log record from the log volume, wherein the log record includes information for restoring a database transaction that is not savepointed to a persistent storage;
interpret a page of a table in the database that is associated with the database transaction as a portion of an index vector that identifies one or more values in a column of the table, wherein the page is stored in the persistent storage;
perform a direct modification of the portion of the index vector and a dictionary based on the log record, wherein the dictionary is associated with the index vector; and
apply the database transaction to the database without replaying the log record as a query, wherein the applying comprises updating the table in the database on the persistent storage based on the modified portion of the index vector and the modified dictionary.

8. The system of claim 7 , wherein the at least one processor is further configured to:
identify the page of the table in the database on the persistent storage, wherein the page is associated with the database transaction.

9. The system of claim 7 , wherein to perform the direct modification of the portion of the index vector and the dictionary based on the database transaction, the at least one processor is configured to:
insert a key in the portion of the index vector and the dictionary based on the database transaction; and
insert a value in the dictionary based on the database transaction.

10. The system of claim 7 , wherein to perform the direct modification of the portion of the index vector and the dictionary based on the database transaction, the at least one processor is configured to:
delete a key in the portion of the index vector based on the database transaction.

11. The system of claim 7 , wherein to perform the direct modification of the portion of the index vector and the dictionary based on the database transaction, the at least one processor is configured to:
alter a key in the portion of the index vector based on the database transaction.

12. The system of claim 7 , wherein the dictionary represents the one or more values in the column of the table.

13. A non-transitory computer-readable device having instructions stored thereon that, when executed by at least one computing device, causes the at least one computing device to perform operations comprising:
reading a log record from a log volume, wherein the log record includes information for restoring a database transaction that is not savepointed to a persistent storage;
interpreting a page of a table in the database that is associated with the database transaction as a portion of an index vector that identifies one or more values in a column of the table, wherein the page is stored in the persistent storage;
performing a direct modification of the portion of the index vector and a dictionary based on the log record, wherein the dictionary is associated with the index vector; and
applying the database transaction to the database without replaying the log record as a query, wherein the applying comprises updating the table in the database on the persistent storage based on the modified portion of the index vector and the modified dictionary.

14. The non-transitory computer-readable device of claim 13 , further comprising:
identifying the page of the table in the database on the persistent storage, wherein the page is associated with the database transaction.

15. The non-transitory computer-readable device of claim 13 , the performing the direct modification comprising:
inserting a key in the portion of the index vector and the dictionary based on the database transaction; and
inserting a value in the dictionary based on the database transaction.

16. The non-transitory computer-readable device of claim 13 , the performing the direct modification comprising:
deleting a key in the portion of the index vector based on the database transaction.

17. The non-transitory computer-readable device of claim 13 , the performing the direct modification comprising:
altering a key in the portion of the index vector based on the database transaction.

18. The non-transitory computer-readable device of claim 13 , wherein the dictionary represents the one or more values in the column of the table.

Assignees

• Schreter Ivan
• Chen Shiping
• Wein David
• Geiβinger Steffen
• Sap Se

Inventors

• Schreter Ivan
• Chen Shiping
• Wein David
• Geiβinger Steffen

Classifications

• G06F16/2365 Primary

  Ensuring data consistency and integrity · CPC title

• G06F16/2358

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

• G06F17/30368

  Physics · mapped topic

• G06F17/30371 Primary

  Physics · mapped topic