System and method for variable block logging with log-ahead buffers

• US 20060036660A1
• Filed: 07/07/2005
• Published: 02/16/2006
• Est. Priority Date: 08/13/2004
• Status: Active Grant

• Current Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Original Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Inventors: Lynn, Joseph B.
• Granted Patent: US 8,090,691 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2308 Concurrency control transaction processing G06F9/466
• CPC Class Codes: G06F 16/2358 Change logging, detection, and notification replication G06F16/27

Abstract

A system for logging database transactions comprises a memory (comprising a direct access storage device) operable to store a database, a database log, and a plurality of log buffers associated with the database log. Each log buffer is operable to store at least one log record associated with a database transaction. The system further comprises a processor operable to log a first record of a first database transaction using the database log and write the database log to the storage device. The processor is further operable to log a second record of a second database transaction in a first of the plurality of log buffers substantially concurrently to the database log being written to the storage device.

Claims

1. A method for logging database transactions, comprising:

logging a first record of a first database transaction using a database log;

writing at least a portion of the database log to a storage device; and

logging a second record of a second database transaction in a first log buffer substantially concurrently to the database log being written to the storage device.

2. The method of claim 1, further comprising:

receiving information associated with a third database transaction; and

in response to the first log buffer being full, logging a third record of the third database transaction in a second log buffer substantially concurrently to the database log being written to the storage device.

3. The method of claim 2, upon completion of the write of the database log to the storage device, the method further comprising:

receiving information associated with a fourth database transaction;

logging a fourth record of the fourth database transaction in the database log; and

writing the first and second log buffers to the storage device using chained input/output.

4. The method of claim 3, upon completion of the write of the first and second log buffers to the storage device, the method further comprising freeing the first and second log buffers.

5. The method of claim 1, further comprising writing the database log to the storage device in response to detecting a trigger event.

6. The method of claim 1, further comprising:

receiving information associated with a third database transaction;

in response to the third transaction comprising a triggering event, logging a third record of a fourth database transaction in a second log buffer substantially concurrently to the database log being written to the storage device; and

writing the first log buffer to the storage device up upon completion of the write of the database log to the storage device.

7. The method of claim 1, wherein a total number of log buffers and a size for each of the log buffers is dynamically determined based on system usage.

8. Software for logging database transactions, the software operable when executed to:

log a first record of a first database transaction using a database log;

write at least a portion of the database log to a storage device; and

log a second record of a second database transaction in a first log buffer substantially concurrently to the database log being written to the storage device.

9. The software of claim 8, further operable to:

receive information associated with a third database transaction; and

in response to the first log buffer being full, log a third record of the third database transaction in a second log buffer substantially concurrently to the database log being written to the storage device.

10. The software of claim 9, upon completion of the write of the database log to the storage device, the software further operable to:

receive information associated with a fourth database transaction;

log a fourth record of the fourth database transaction in the database log; and

write the first and second log buffers to the storage device using chained input/output.

11. The software of claim 10, upon completion of the write of the first and second log buffers to the storage device, the software further operable to free the first and second log buffers.

12. The software of claim 8, further operable to write the database log to the storage device in response to detecting a trigger event.

13. The software of claim 8, further operable to write the database log to the storage device in response to the database log being full.

14. The software of claim 8, further operable to:

receive information associated with a third database transaction;

in response to the third transaction comprising a triggering event, log a third record of a fourth database transaction in a second log buffer substantially concurrently to the database log being written to the storage device; and

write the first log buffer to the storage device up upon completion of the write of the database log to the storage device.

15. The software of claim 8, wherein a total number of log buffers and a size for each of the log buffers is dynamically determined based on system usage.

16. A system for logging database transactions, comprising:

a memory storing a database, a database log, and a plurality of log buffers associated with the database log, each log buffer operable to store at least one log record associated with a database transaction, and the memory comprising a direct access storage device; and

a processor operable to;

log a first record of a first database transaction using the database log;

write at least a portion of the database log to the storage device; and

log a second record of a second database transaction in a first of the plurality of log buffers substantially concurrently to the database log being written to the storage device.

17. The system of claim 16, the processor further operable to:

receive information associated with a third database transaction; and

in response to the first log buffer being full, log a third record of the third database transaction in a second of the plurality of log buffers substantially concurrently to the database log being written to the storage device.

18. The system of claim 17, upon completion of the write of the database log to the storage device, the processor further operable to:

receive information associated with a fourth database transaction;

log a fourth record of the fourth database transaction in the database log; and

write the first and second log buffers to the storage device using chained input/output.

19. The system of claim 18, upon completion of the write of the first and second log buffers to the storage device, the processor further operable to free the first and second log buffers.

20. The system of claim 16, the processor further operable to write the database log to the storage device in response to detecting a trigger event.

21. The system of claim 16, the processor further operable to:

receive information associated with a third database transaction;

in response to the third transaction comprising a triggering event, log a third record of a fourth database transaction in a second of the plurality of log buffers substantially concurrently to the database log being written to the storage device; and

write the first log buffer to the storage device up upon completion of the write of the database log to the storage device.

22. The system of claim 16, wherein a total number of log buffers and a size for each of the plurality of log buffers is dynamically determined based on system usage.