Compaction Iterator Bug

I am not sure if this is a bug with the FileCompactor, the SlowIterator or not a bug at all. While testing 2.1 with my changes in #2541, I have Uno setup to run the SlowIterator during a compaction of some CI data. The compaction will start up but it won’t get registered in ZK under the fate directory. It will never make it past this section of code in FileCompactor:

  while (itr.hasTop() && env.isCompactionEnabled()) {
      mfw.append(itr.getTopKey(), itr.getTopValue());
      itr.next();
      entriesCompacted++;

      if (entriesCompacted % 1024 == 0) {
        // Periodically update stats, do not want to do this too often since its volatile
        entriesWritten.addAndGet(1024);
      }
    }

I assume the source of the SlowIterator will always return true for hasTop(), hence why it never makes it past this code. It could just be a bug when using the SlowIterator with compactions. But if a user creates an iterator that does something similiar, I wonder if it will run indefinitely. Also, I only have the sleepTime of the SlowIterator configured for 5ms.

[Manno15]

@milleruntime Only one way to find out. You definitely have to run it for 4+ hours now…

[dlmarion]

I’m not seeing the link between the code and the compaction not showing up in ZK.