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Question and Answer

Tom Kyte

Thanks for the question.

Asked: March 23, 2001 - 1:29 pm UTC

Last updated: June 22, 2006 - 2:53 pm UTC

Version: 8.1.7

Viewed 1000+ times

You Asked

What is RBA ?
What do these hex numbers mean ?
I saw this in the alert log

Oralcel 8.1.7

Mon Mar 5 21:47:26 2001
Completed checkpoint up to RBA [0x1c5.2.10], SCN: 0x0000.00047fc0
Tue Mar 6 20:45:21 2001
Beginning log switch checkpoint up to RBA [0x1c6.2.10], SCN: 0x0000.00047fd1
Thread 1 advanced to log sequence 454


and we said...

Redo Byte Address (RBA)

An RBA points to a specific location in a particular redo thread. It
is ten bytes long and has three components: log sequence number,
block number within log, and byte number within block.


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RBA associated with fast start checkpointing

Y Srinivas, March 26, 2001 - 2:05 am UTC

After reading this answer I recollect that now checkpointing is done at the block level (fast start checkpointing). Is the RBA address the last block used for checkpointing?

Contents of RBA

Santosh Hiremath, April 29, 2005 - 9:08 am UTC

How the RBA is generated.

Thanks and Regards,
Santosh from Bangalore.

If you have a time please explain me how exactly it is useful.



A reader, June 22, 2006 - 1:17 pm UTC

Hi Tom,

I would be thankful to you if you kindly explain this below line in detain or with EXAMPLE.

"Given a checkpoint RBA, DBWR writes buffers from the head of the queue until the low RBA of the buffer at the head of the checkpoint queue is greater than the checkpoint RBA."


Tom Kyte
June 22, 2006 - 2:53 pm UTC

let me just rephrase.

It is as straight forward as it looks in this case, don't over analyze it. Pretend the checkpoint rba is a "time". dbwr flushed out blocks to disk older than that time.