[HBASE-9751] Excessive readpoints checks in StoreFileScanner

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.98.0, 0.94.12, 0.96.0
• Fix Version/s: 0.98.0, 0.94.13, 0.96.1
• Hadoop Flags: Reviewed
• Assignee: Lars Hofhansl
• Reporter: Vladimir Rodionov
• Created: 12/Oct/13 04:41
• Updated: 08/Nov/13 00:03
• Resolved: 14/Oct/13 04:01

Description

It seems that usage of skipKVsNewerThanReadpoint in StoreFileScanner can be greatly reduced or even eliminated all together (HFiles are immutable and no new KVs can be inserted after scanner instance is created). The same is true for MemStoreScanner which checks readpoint on every next() and seek(). Each readpoint check is ThreadLocal.get() and it is quite expensive.