private long allocate(long suggestedOffset, int length) {
    if (suggestedOffset + length > maxOplogSize) {
      flushAll();
      doneAppending = true;
      return -1;
    } else {
      return suggestedOffset;
    }
  }
The number of records in this oplog that contain the most recent value of the entry.
geode-core/src/main/java/org/apache/geode/internal/cache/OverflowOplog.java