[HBASE-12948] Calling Increment#addColumn on the same column multiple times produces wrong result

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 1.0.1, 1.1.0, 0.98.11, 2.0.0
• Component/s: Client, regionserver
• Hadoop Flags: Reviewed
• Assignee: hongyu bi
• Reporter: hongyu bi
• Created: 30/Jan/15 14:18
• Updated: 28/Apr/15 19:19
• Resolved: 17/Feb/15 21:19

Description

Case:
Initially get('row1'):
rowkey=row1 value=1
run:
Increment increment = new Increment(Bytes.toBytes("row1"));
for (int i = 0; i < N; i++) {
increment.addColumn(Bytes.toBytes("cf"), Bytes.toBytes("c"), 1)
}
hobi.increment(increment);

get('row1'):
if N=1 then result is 2 else if N>1 the result will always be 1

Cause:
https://issues.apache.org/jira/browse/HBASE-7114 let increment extent mutation which change familyMap from NavigableMap to List, so from client side, we can buffer many edits on the same column；
However, HRegion#increment use idx to iterate the get's results, here results.size<family.value().size if N>1，so the latter edits on the same column won't match the condition

{idx < results.size() && CellUtil.matchingQualifier(results.get(idx), kv) }

, meantime the edits share the same mvccVersion ,so this case happen.

Fix:
according to the put/delete#add on the same column behaviour ,
fix from server side: process "last edit wins on the same column" inside HRegion#increment to maintenance HBASE-7114's extension and keep the same result from 0.94.