code: @Override
      public void delete(DecoratedKey key, OpOrder.Group opGroup) {
          Log.debug("Removing row %s from index %s", key, logName);
          lock.writeLock().lock();
          try {
              rowService.delete(key);
              rowService = null;
          } catch (RuntimeException e) {
              Log.error(e, "Error deleting row %s", key);
              throw e;
          } finally {
              lock.writeLock().unlock();
          }
      }
docs: cleans up deleted columns from cassandra cleanup compaction
  
  @param key The partition key of the physical row to be deleted.