langgenius/dify · error · NotFound

Dataset not found.

Error message

Dataset not found.

What it means

Raised by the create-child-chunk POST handler when DatasetService.get_dataset returns None for the given dataset_id. The dataset was not found in the current tenant/session, so the controller aborts with NotFound (HTTP 404) before any further validation.

Source

Thrown at api/controllers/console/datasets/datasets_segments.py:719

    @with_current_tenant_id
    @rbac_permission_required(RBACResourceScope.DATASET, RBACPermission.DATASET_EDIT)
    @with_session
    @model_validate(ChildChunkCreatePayload)
    def post(
        self,
        req_data: ChildChunkCreatePayload,
        session: Session,
        current_tenant_id: str,
        current_user: Account,
        dataset_id: UUID,
        document_id: UUID,
        segment_id: UUID,
    ):
        # check dataset
        dataset_id_str = str(dataset_id)
        dataset = DatasetService.get_dataset(dataset_id_str, session)
        if not dataset:
            raise NotFound("Dataset not found.")
        # check document
        document_id_str = str(document_id)
        document = DocumentService.get_document(dataset_id_str, document_id_str, session=session)
        if not document:
            raise NotFound("Document not found.")
        if not current_user.is_dataset_editor:
            raise Forbidden()
        try:
            DatasetService.check_dataset_permission(dataset, current_user, session)
        except services.errors.account.NoPermissionError as e:
            raise Forbidden(str(e))
        # check embedding model setting
        if dataset.indexing_technique == IndexTechniqueType.HIGH_QUALITY:
            try:
                model_manager = ModelManager.for_tenant(tenant_id=current_tenant_id)
                model_manager.get_model_instance(
                    tenant_id=current_tenant_id,
                    provider=dataset.embedding_model_provider,

View on GitHub (pinned to ef8544b173)

Solutions

1. Verify the dataset_id is correct for the current tenant by listing datasets first.
2. If the dataset was deleted, recreate or restore it and use the new id.
3. Refresh the parent resources in the UI before opening the child-chunk editor to avoid stale ids.

Example fix

// before
POST /datasets/{wrong_dataset_id}/documents/{doc_id}/segments/{seg_id}/child_chunks
// after
GET /datasets -> find correct dataset_id
POST /datasets/{correct_dataset_id}/documents/{doc_id}/segments/{seg_id}/child_chunks

async function ensureDataset(datasetId) {
  const r = await fetch(`/console/api/datasets/${datasetId}`);
  if (!r.ok) throw new Error('dataset not found; refresh the dataset id');
  return r.json();
}

const isValidDatasetId = (id) => typeof id === 'string' && /^[0-9a-fA-F-]{36}$/.test(id);

try {
  await ensureDataset(datasetId);
  await createChildChunk({datasetId, documentId, segmentId, content});
} catch (e) {
  if (e.status === 404) { /* refresh ids, do not auto-retry destructively */ throw e; }
  throw e;
}

When it happens

Trigger: POST /console/api/datasets/{dataset_id}/documents/{document_id}/segments/{segment_id}/child_chunks with a dataset_id that does not exist, was deleted, or belongs to a different tenant.

Common situations: Wrong dataset_id copied from another workspace; dataset was archived or hard-deleted between page load and the request; URL was constructed from stale frontend state.

Related errors

• Document not found.
• UploadFile not found.
• The job does not exist.
• Child chunk not found.
• API template not found.

AI-assisted analysis of langgenius/dify@ef8544b173 (2026-08-12). Data as JSON: /api/errors/67fdec256465da85. Report an issue: GitHub.