[HBASE-13417] batchCoprocessorService() does not handle NULL keys

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.0.0
• Fix Version/s: 1.1.0, 0.98.13, 1.0.2, 2.0.0
• Component/s: Coprocessors
• Labels: beginner
• Assignee: Abhishek Singh Chouhan
• Reporter: Lars George
• Created: 07/Apr/15 07:27
• Updated: 03/Jul/15 23:32
• Resolved: 28/Apr/15 23:46

Description

The JavaDoc for batchCoprocessorService() reads:

* @param startKey
*          start region selection with region containing this row. If {@code null}, the
*          selection will start with the first table region.
* @param endKey
*          select regions up to and including the region containing this row. If {@code null},
*          selection will continue through the last table region.

Setting the call to null keys like so

      Map<byte[], CountResponse> results = table.batchCoprocessorService(
        RowCountService.getDescriptor().findMethodByName("getRowCount"),
        request, null, null, CountResponse.getDefaultInstance());

yields an exception:

java.lang.NullPointerException
	at org.apache.hadoop.hbase.util.Bytes.compareTo(Bytes.java:1187)
	at org.apache.hadoop.hbase.client.HTable.getKeysAndRegionsInRange(HTable.java:744)
	at org.apache.hadoop.hbase.client.HTable.getKeysAndRegionsInRange(HTable.java:723)
	at org.apache.hadoop.hbase.client.HTable.batchCoprocessorService(HTable.java:1801)
	at org.apache.hadoop.hbase.client.HTable.batchCoprocessorService(HTable.java:1778)
	at coprocessor.EndpointBatchExample.main(EndpointBatchExample.java:60)
	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:606)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)

This is caused by the call shipping off the keys to getStartKeysInRange() as-is and that method uses Bytes.compareTo() on the null keys and fails.

One can work around using HConstants.EMPTY_START_ROW, HConstants.EMPTY_END_ROW instead, but that is not documented, nor standard behavior. Need to handle null keys as advertised.