[HBASE-5121] MajorCompaction may affect scan's correctness

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.90.4
• Fix Version/s: 0.92.1, 0.94.0
• Component/s: regionserver
• Hadoop Flags: Reviewed
• Assignee: Chunhui Shen
• Reporter: Chunhui Shen
• Created: 04/Jan/12 06:39
• Updated: 12/Oct/12 05:34
• Resolved: 10/Jan/12 23:41

Description

In our test, there are two families' keyvalue for one row.

But we could find a infrequent problem when doing scan's next if majorCompaction happens concurrently.
In the client's two continuous doing scan.next():
1.First time, scan's next returns the result where family A is null.
2.Second time, scan's next returns the result where family B is null.
The two next()'s result have the same row.

If there are more families, I think the scenario will be more strange...

We find the reason is that storescanner.peek() is changed after majorCompaction if there are delete type KeyValue.
This change causes the PriorityQueue<KeyValueScanner> of RegionScanner's heap is not sure to be sorted.

Issue Links

• relates to: HBASE-5659 TestAtomicOperation.testMultiRowMutationMultiThreads is still failing occasionally
• relates to: HBASE-2856 TestAcidGuarantee broken on trunk