[HBASE-4197] RegionServer expects all scanner to be subclasses of HRegion.RegionScanner

• 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: Incompatible change, Reviewed
• Release Note: RegionScanner is now an interface which extends InternalScanner.
• Assignee: Lars Hofhansl
• Reporter: Lars Hofhansl
• Created: 12/Aug/11 17:26
• Updated: 20/Nov/15 11:54
• Resolved: 20/Aug/11 05:07

Description

Returning just an InternalScanner from RegionObsever.

{pre|post}

OpenScanner leads to the following exception when using the scanner.

java.io.IOException: InternalScanner implementation is expected to be HRegion.RegionScanner.
at org.apache.hadoop.hbase.regionserver.HRegionServer.next(HRegionServer.java:2023)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.apache.hadoop.hbase.ipc.WritableRpcEngine$Server.call(WritableRpcEngine.java:314)
at org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1225)

The problem is in HRegionServer.next(...):

 
    InternalScanner s = this.scanners.get(scannerName);
...
      // Call coprocessor. Get region info from scanner.
      HRegion region = null;
      if (s instanceof HRegion.RegionScanner) {
        HRegion.RegionScanner rs = (HRegion.RegionScanner) s;
        region = getRegion(rs.getRegionName().getRegionName());
      } else {
        throw new IOException("InternalScanner implementation is expected " +
            "to be HRegion.RegionScanner.");
      }