apache/iceberg · error · NoSuchNamespaceException

Namespace does not exist: %s

Error message

Namespace does not exist: %s

What it means

listNamespaces(Namespace) in BigQueryMetastoreCatalog only supports listing the single level of datasets: it requires an empty namespace argument (listing all datasets). Passing any non-empty namespace throws NoSuchNamespaceException because nested namespaces do not exist in this catalog.

Source

Thrown at bigquery/src/main/java/org/apache/iceberg/gcp/bigquery/BigQueryMetastoreCatalog.java:217

  }

  @Override
  public List<Namespace> listNamespaces() {
    try {
      return listNamespaces(Namespace.empty());
    } catch (NoSuchNamespaceException e) {
      return ImmutableList.of();
    }
  }

  /**
   * Since this catalog only supports one-level namespaces, it always returns an empty list unless
   * passed an empty namespace to list all namespaces within the catalog.
   */
  @Override
  public List<Namespace> listNamespaces(Namespace namespace) {
    if (!namespace.isEmpty()) {
      throw new NoSuchNamespaceException("Namespace does not exist: %s", namespace);
    }

    List<Datasets> allDatasets = client.list(projectId);

    ImmutableList<Namespace> namespaces =
        allDatasets.stream().map(this::toNamespace).collect(ImmutableList.toImmutableList());

    if (namespaces.isEmpty()) {
      throw new NoSuchNamespaceException("Namespace does not exist: %s", namespace);
    }

    return namespaces;
  }

  @Override
  public boolean dropNamespace(Namespace namespace) {
    try {
      client.delete(toDatasetReference(namespace));

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Call listNamespaces() with no arguments (empty namespace) to list all datasets.
2. Treat the catalog as single-level: list tables within a dataset via listTables instead of listing sub-namespaces.
3. Filter engine namespace exploration logic to not recurse into namespaces for this catalog.

Example fix

// before
List<Namespace> ns = catalog.listNamespaces(Namespace.of("myDataset"));
// after
List<Namespace> ns = catalog.listNamespaces(); // all datasets in the catalog
List<TableIdentifier> tables = catalog.listTables(Namespace.of("myDataset"));

if (!namespace.isEmpty()) { throw new IllegalArgumentException("BigQuery catalog supports only single-level namespaces; call listNamespaces() with no arguments"); }

try { namespaces = catalog.listNamespaces(ns); } catch (NoSuchNamespaceException e) { namespaces = catalog.listNamespaces(); }

When it happens

Trigger: Calling catalog.listNamespaces(Namespace.of("someDataset")) or any engine API that lists the children of a named namespace.

Common situations: Engine metadata browsing that tries to list sub-namespaces of a dataset; code ported from catalogs (e.g. JDBC/Hive) that support hierarchical namespaces.

Related errors

• Table rename operation is unsupported.
• Creating BigQuery client failed
• Creating BigQuery client failed due to a security issue
• %s
• Namespace already exists: %s

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/127a44a488ba63ba. Report an issue: GitHub.