[HBASE-6200] KeyComparator.compareWithoutRow can be wrong when families have the same prefix

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.90.6, 0.92.1, 0.94.0
• Fix Version/s: 0.92.2, 0.94.1, 0.95.0
• Hadoop Flags: Reviewed
• Assignee: Jieshan Bean
• Reporter: Jean-Daniel Cryans
• Created: 11/Jun/12 21:37
• Updated: 18/Sep/13 20:00
• Resolved: 27/Jun/12 07:08

Description

As reported by Desert Rose on IRC and on the ML, Result has a weird behavior when some families share the same prefix. He posted a link to his code to show how it fails, http://pastebin.com/7TBA1XGh

Basically KeyComparator.compareWithoutRow doesn't differentiate families and qualifiers so "f:a" is said to be bigger than "f1:", which is false. Then what happens is that the KVs are returned in the right order from the RS but then doing Result.binarySearch it uses KeyComparator.compareWithoutRow which has a different sorting so the end result is undetermined.

I added some debug and I can see that the data is returned in the right order but Arrays.binarySearch returned the wrong KV, which is then verified agains the passed family and qualifier which fails so null is returned.

I don't know how frequent it is for users to have families with the same prefix, but those that do have that and that use those families at the same time will have big correctness issues. This is why I mark this as a blocker.

Issue Links

• is related to: HBASE-5915 Improve performance of KeyValue comparison