[MAPREDUCE-90] incrementing counters should not be used for triggering record skipping

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Assignee: Unassigned
• Reporter: Owen O'Malley
• Created: 24/Nov/08 21:56
• Updated: 07/Jul/12 16:16
• Resolved: 07/Jul/12 16:16

Description

The following code is really problematic:

public void incrCounter(String group, String counter, long amount) {
  if (counters != null) {
    counters.incrCounter(group, counter, amount);
  }
  if(skipping && SkipBadRecords.COUNTER_GROUP.equals(group) && (
     SkipBadRecords.COUNTER_MAP_PROCESSED_RECORDS.equals(counter) ||
     SkipBadRecords.COUNTER_REDUCE_PROCESSED_GROUPS.equals(counter))) {
     //if application reports the processed records, move the 
     //currentRecStartIndex to the next.
     //currentRecStartIndex is the start index which has not yet been 
     //finished and is still in task's stomach.
     for(int i=0;i<amount;i++) {
        currentRecStartIndex = currentRecIndexIterator.next();
     }
   ...
}

In particular, if the user updates a counter with the wrong name, bad things will presumably happen...