[HBASE-533] Region Historian

• Type: Wish
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.2.0
• Assignee: Jean-Daniel Cryans
• Reporter: Bryan Duxbury
• Created: 19/Mar/08 23:37
• Updated: 22/Aug/08 21:13
• Resolved: 04/Jun/08 17:20

Description

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.

Issue Links

• is blocked by: HBASE-660 [Migration] addColumn/deleteColumn functionality in MetaUtils