apache/hadoop · error · UnsupportedOperationException

Remote Iterator issupported for snapshotDiffReport between t

Error message

Remote Iterator issupported for snapshotDiffReport between two snapshots

What it means

Error "Remote Iterator issupported for snapshotDiffReport between two snapshots" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java:2474

   *          tree
   * @param toSnapshot
   *          snapshot name of the to point. Null indicates the current
   *          tree.
   * @return Remote iterator
   */
  public RemoteIterator
      <SnapshotDiffReportListing> snapshotDiffReportListingRemoteIterator(
      final Path snapshotDir, final String fromSnapshot,
      final String toSnapshot) throws IOException {
    Path absF = fixRelativePart(snapshotDir);
    return new FileSystemLinkResolver
        <RemoteIterator<SnapshotDiffReportListing>>() {
      @Override
      public RemoteIterator<SnapshotDiffReportListing> doCall(final Path p)
          throws IOException {
        if (!DFSUtilClient.isValidSnapshotName(fromSnapshot) ||
            !DFSUtilClient.isValidSnapshotName(toSnapshot)) {
          throw new UnsupportedOperationException("Remote Iterator is"
              + "supported for snapshotDiffReport between two snapshots");
        }
        return new SnapshotDiffReportListingIterator(getPathName(p),
            fromSnapshot, toSnapshot);
      }

      @Override
      public RemoteIterator<SnapshotDiffReportListing> next(final FileSystem fs,
          final Path p) throws IOException {
        return ((DistributedFileSystem) fs)
            .snapshotDiffReportListingRemoteIterator(p, fromSnapshot,
                toSnapshot);
      }
    }.resolve(this, absF);

  }

  /**

View on GitHub (pinned to 2add963021)

Solutions

1. Call snapshotDiffReport with both fromSnapshot and toSnapshot specified when using the remote iterator API.
2. Use the non-iterator snapshotDiffReport for comparisons that omit one snapshot.

When it happens

Trigger: snapshotDiffReport is requested with an iterator, but the FileSystem or path does not support the remote-iterator variant for diff reports between two snapshots.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/22a93b2619fa143a. Report an issue: GitHub.