[HBASE-3583] Coprocessors: RegionObserver: ScannerNext and ScannerClose hooks are called when get() is invoked

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.92.0
• Fix Version/s: 0.92.0
• Component/s: Coprocessors
• Hadoop Flags: Reviewed
• Assignee: Mingjie Lai
• Reporter: Mingjie Lai
• Created: 28/Feb/11 23:25
• Updated: 20/Nov/15 12:42
• Resolved: 24/Mar/11 06:29

Description

RegionObserver upcalls are expected to be triggered by corresponding client calls.

I found that if a HTable.get() is issued, ScannerNext, and ScannerClose hooks are also invoked.

Here is the reason: HRegion.get() is implemented with an internal scanner:

    InternalScanner scanner = null;
    try {
      scanner = getScanner(scan);
      scanner.next(results);
    } finally {
      if (scanner != null)
        scanner.close();
    }

where scanner.next, and scanner.close() are implemented with RegionObserver hooks.