apache/iceberg · error · AlreadyExistsException

Already exists

Error message

Already exists

What it means

InMemoryOutputFile.create() enforces create-new semantics: it throws AlreadyExistsException if the file already exists in the parent InMemoryFileIO. Use createOrOverwrite() when replacing an existing file is intended.

Solutions

1. Use createOrOverwrite() instead of create() when the file may legitimately already exist.
2. Delete the existing file (io.deleteFile(location)) before create(), or use a unique location per write.
3. Catch org.apache.iceberg.exceptions.AlreadyExistsException if the duplicate is expected and should be skipped.

Example fix

// before
OutputFile out = io.newOutputFile(location);
try (PositionOutputStream s = out.create()) { ... } // throws if exists
// after
try (PositionOutputStream s = out.createOrOverwrite()) { ... }

if (out instanceof InMemoryOutputFile && ((InMemoryOutputFile) out).exists()) { /* delete or use createOrOverwrite */ }

try {
  out.create();
} catch (AlreadyExistsException e) {
  out.createOrOverwrite(); // or skip
}

When it happens

Trigger: Calling InMemoryOutputFile.create() (or outputStream(), which delegates to create()) for a location that already has bytes; writing the same location twice via create(); re-running a task that writes without cleaning up first.

Common situations: Retried test setup that re-creates files at fixed locations; assuming create() overwrites like Hadoop's create(overwrite=true); writing manifest/data files to reused in-memory locations across test runs sharing the static map.

Understand the failure class

Background: "already exists" / EEXIST / FileAlreadyExistsException: what the 'file already exists' error means and how to fix it — this error's family across 37 libraries.

Related errors

• Cannot create namespace
• Cannot rename to . Table already exists
• Namespace already exists
• Namespace already exists
• No in-memory file found for location

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/814178e6ee2169a2. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/apache/iceberg/inmemory/InMemoryOutputFile.java:68

   * files are populated into the parentFileIO through other means).
   *
   * @param location the location returned by location() of this OutputFile, the InputFile obtained
   *     from calling toInputFile(), and the location for looking up the associated InputFile from a
   *     parentFileIO, if non-null.
   * @param parentFileIO if non-null, commits an associated InMemoryInputFile on close() into the
   *     parentFileIO, and uses the parentFileIO for "already exists" checks if creating without
   *     overwriting.
   */
  public InMemoryOutputFile(String location, InMemoryFileIO parentFileIO) {
    Preconditions.checkNotNull(location, "location is null");
    this.location = location;
    this.parentFileIO = parentFileIO;
  }

  @Override
  public PositionOutputStream create() {
    if (exists || (parentFileIO != null && parentFileIO.fileExists(location))) {
      throw new AlreadyExistsException("Already exists");
    }
    return createOrOverwrite();
  }

  @Override
  public PositionOutputStream createOrOverwrite() {
    exists = true;
    contents = new ByteArrayOutputStream();
    return new InMemoryPositionOutputStream(contents);
  }

  @Override
  public String location() {
    return location;
  }

  @Override
  public InputFile toInputFile() {

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