apache/hadoop · error · IOException

No more available IDs.

Error message

No more available IDs.

What it means

Error "No more available IDs." thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/CacheManager.java:352

  /**
   * @return Unmodifiable view of the collection of CacheDirectives.
   */
  public Collection<CacheDirective> getCacheDirectives() {
    assert namesystem.hasReadLock(RwLockMode.FS);
    return Collections.unmodifiableCollection(directivesById.values());
  }
  
  @VisibleForTesting
  public GSet<CachedBlock, CachedBlock> getCachedBlocks() {
    assert namesystem.hasReadLock(RwLockMode.BM);
    return cachedBlocks;
  }

  private long getNextDirectiveId() throws IOException {
    assert namesystem.hasWriteLock(RwLockMode.FS);
    if (nextDirectiveId >= Long.MAX_VALUE - 1) {
      throw new IOException("No more available IDs.");
    }
    return nextDirectiveId++;
  }

  // Helper getter / validation methods

  private static void checkWritePermission(FSPermissionChecker pc,
      CachePool pool) throws AccessControlException {
    if ((pc != null)) {
      pc.checkPermission(pool, FsAction.WRITE);
    }
  }

  private static String validatePoolName(CacheDirectiveInfo directive)
      throws InvalidRequestException {
    String pool = directive.getPool();
    if (pool == null) {
      throw new InvalidRequestException("No pool specified.");

View on GitHub (pinned to 2add963021)

Solutions

1. Remove unused cache directives to free directive IDs, or restart the NameNode to reset the ID counter after cleanup.

When it happens

Trigger: Cache directive creation when the CacheManager has exhausted its ID space.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/79a24946e50324e5. Report an issue: GitHub.