[HBASE-15296] Break out writer and reader from StoreFile

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Fix Version/s: 2.0.0
• Component/s: regionserver
• Hadoop Flags: Incompatible change, Reviewed

Release Note

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Refactor that breaks out StoreFile Reader and Writer inner classes as StoreFileReader and StoreFileWriter.

NOTE! Changes RegionObserver Coprocessor Interface so incompatible change (Discussed on dev list in thread "[Note breaking change on RegionObserver in hbase-2.0.0](https://s.apache.org/hbase-dev-note-about-HBASE-15296)"

• Assignee: Apekshit Sharma
• Reporter: Apekshit Sharma
• Created: 20/Feb/16 02:28
• Updated: 11/May/17 03:54
• Resolved: 11/May/17 03:49

Description

StoreFile.java is trending to become a monolithic class, it's ~1800 lines. Would it make sense to break out reader and writer (~500 lines each) into separate files.

We are doing so many different things in a single class: comparators, reader, writer, other stuff; and it hurts readability a lot, to the point that just reading through a piece of code require scrolling up and down to see which level (reader/writer/base class level) it belongs to. These small-small things really don't help while trying to understanding the code. There are good reasons we don't do these often (affects existing patches, needs to be done for all branches, etc). But this and a few other classes can really use a single iteration of refactoring to make things a lot better.

Issue Links

• relates to: HBASE-18029 Backport HBASE-15296 to branch-1
• links to: Review Board (branch-1)