[HBASE-6846] BitComparator bug - ArrayIndexOutOfBoundsException

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.94.1
• Fix Version/s: 0.94.3, 0.95.0
• Component/s: Filters

Environment

HBase 0.94.1 + Hadoop 2.0.0-cdh4.0.1

• Release Note: BitComparator bug - ArrayIndexOutOfBoundsException corrected
• Assignee: Lucian George Iordache
• Reporter: Lucian George Iordache
• Created: 20/Sep/12 14:33
• Updated: 26/Feb/13 08:21
• Resolved: 27/Oct/12 21:29

Description

The HBase 0.94.1 BitComparator introduced a bug in the method "compareTo":

@Override
  public int compareTo(byte[] value, int offset, int length) {
    if (length != this.value.length) {
      return 1;
    }
    int b = 0;
    //Iterating backwards is faster because we can quit after one non-zero byte.
    for (int i = value.length - 1; i >= 0 && b == 0; i--) {
      switch (bitOperator) {
        case AND:
          b = (this.value[i] & value[i+offset]) & 0xff;
          break;
        case OR:
          b = (this.value[i] | value[i+offset]) & 0xff;
          break;
        case XOR:
          b = (this.value[i] ^ value[i+offset]) & 0xff;
          break;
      }
    }
    return b == 0 ? 1 : 0;
  }

I've encountered this problem when using a BitComparator with a configured this.value.length=8, and in the HBase table there were KeyValues with keyValue.getBuffer().length=207911 bytes. In this case:

    for (int i = 207910; i >= 0 && b == 0; i--) {
      switch (bitOperator) {
        case AND:
          b = (this.value[207910] ... ==> ArrayIndexOutOfBoundsException
          break;

That loop should use:

  for (int i = length - 1; i >= 0 && b == 0; i--) { (or this.value.length.)

Should I provide a patch for correcting the problem?