mongodb/node-mongodb-native · error · MongoRuntimeError

A collection name must be determined before getMore

Error message

A collection name must be determined before getMore

What it means

Thrown as a MongoRuntimeError by GetMoreOperation.buildCommand when the cursor's namespace has no collection name (this.ns.collection == null). getMore must address a concrete collection, and the cursor should have adopted the namespace returned by the server. A null collection indicates the cursor namespace was never set or was corrupted, which is an internal/driver-level defect rather than typical user input.

Solutions

1. If reproducing in user code, ensure you create cursors via the standard APIs (collection.find/aggregate) which set the namespace.
2. Report the reproduction to the driver maintainers; this guard typically signals an internal defect.
3. Avoid manually constructing or mutating cursor namespaces.

try {
  await cursor.next();
} catch (err) {
  if (err instanceof MongoRuntimeError && /collection name must be determined before getMore/.test(err.message)) {
    // namespace not adopted; recreate the cursor via a collection-scoped query
  } else throw err;
}

When it happens

Trigger: Issuing getMore on a cursor whose namespace.collection is null/undefined. This can happen with certain collection-less commands (e.g. some aggregate against a database) where the server's namespace adoption did not populate a pseudo collection name, or via internal cursor misuse.

Common situations: Driver bugs in namespace adoption; constructing cursors directly in tests without a namespace; edge cases with db-level aggregate/changeStream pipelines.

Related errors

• A collection name must be determined before killCursors
• Unable to iterate cursor with no id
• An unexpected error type
• A query document must be specified for query
• Argument for maxTimeMS must be a number

AI-assisted analysis of mongodb/node-mongodb-native@dce7939f86 (2026-08-11). Data as JSON: /api/errors/54dd61c943cbc5c8. Report an issue: GitHub.

Appendix: source

Thrown at src/operations/get_more.ts:65

    this.ns = ns;
    this.cursorId = cursorId;
    this.server = server;
  }

  override get commandName() {
    return 'getMore' as const;
  }

  override buildCommand(_connection: Connection): Document {
    if (this.cursorId == null || this.cursorId.isZero()) {
      throw new MongoRuntimeError('Unable to iterate cursor with no id');
    }

    const collection = this.ns.collection;
    if (collection == null) {
      // Cursors should have adopted the namespace returned by MongoDB
      // which should always defined a collection name (even a pseudo one, ex. db.aggregate())
      throw new MongoRuntimeError('A collection name must be determined before getMore');
    }

    const getMoreCmd: GetMoreCommand = {
      getMore: this.cursorId,
      collection
    };

    if (typeof this.options.batchSize === 'number') {
      getMoreCmd.batchSize = Math.abs(this.options.batchSize);
    }

    if (typeof this.options.maxAwaitTimeMS === 'number') {
      getMoreCmd.maxTimeMS = this.options.maxAwaitTimeMS;
    }

    // we check for undefined specifically here to allow falsy values
    // eslint-disable-next-line no-restricted-syntax
    if (this.options.comment !== undefined) {

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