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https://issues.apache.org/jira/browse/HBASE-533?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12600790#action_12600790
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Jean-Daniel Cryans commented on HBASE-533:
------------------------------------------

Parents logs end up in the daughter entries because they are deleted from 
.META. so if depth is set to 1, we will lose information all that time. Setting 
to two 2 after a reboot won't recover information.

Ok for the text.

Ok for the split with the address, I'lls see what I can do. It will be the same 
for merge.

Regards compaction, I just included the time it took and just as Google with 
Bigtable, this can be useful to asses performance. So I suggest we keep it in 
the DEBUG level.

Regards log level, it's already in my code and it took 2 lines. Won't be hard 
to modify.

> Region Historian
> ----------------
>
>                 Key: HBASE-533
>                 URL: https://issues.apache.org/jira/browse/HBASE-533
>             Project: Hadoop HBase
>          Issue Type: Wish
>            Reporter: Bryan Duxbury
>            Assignee: Jean-Daniel Cryans
>            Priority: Minor
>         Attachments: hbase-533-v1-fix.patch, hbase-533-v1.patch
>
>
> Whenever we try to debug region splitting, assignment, compaction, etc. 
> issues, we always end up having to look in 1-20 different log files for 
> cryptic names of regions and try to piece together the chain of events 
> ourselves. This is a challenging at best effort most of the time.
> What would be very useful would be a new utility I've nicknamed the Region 
> Historian. You give it the text name of a region, and it will track down the 
> log messages relevant to it in the master and regionserver logs. Then, it 
> will interleave the messages in such a way that the timestamps correctly list 
> the order of events. The result is a log summary that accurately describes 
> what happened to a region during it's lifetime, making it much easier to try 
> and figure out where something went wrong.
> Other things it could do would be replace cryptic log messages with simple 
> events like "the region was split into a and b", "the region was assigned to 
> server x", and trace the lineage of a region backwards to its parent before 
> it came into existence.
> I'm sure there are other things we would think up that would be useful as 
> well.

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