private boolean journalRebuildRequired() {
    final int redundantOpCompactThreshold = 2000;
    return redundantOpCount >= redundantOpCompactThreshold //
        && redundantOpCount >= lruEntries.size();
  }
We only rebuild the journal when it will halve the size of the journal
and eliminate at least 2000 ops.
core/src/main/java/com/bumptech/glide/disklrucache/DiskLruCache.java