langflow-ai/langflow · error · HTTPException

Failed to persist knowledge base '{kb_name}' with backend '{

Error message

Failed to persist knowledge base '{kb_name}' with backend '{backend_type_value}'. Please retry.

What it means

Error "Failed to persist knowledge base '{kb_name}' with backend '{backend_type_value}'. Please retry." thrown in langflow-ai/langflow.

Source

Thrown at src/backend/base/langflow/api/v1/knowledge_bases.py:849

            }
            await knowledge_base_service.create_record(
                user_id=current_user.id,
                name=kb_name,
                model_selection=persisted_selection,
                column_config=column_config_dicts or [],
                backend_type=backend_type_value,
                backend_config=backend_config_value,
                record_id=kb_id,
            )
        except Exception as exc:
            await logger.aerror(
                "KB DB persist failed for backend %s (kb=%s): %s — rolling back",
                backend_type_value,
                kb_name,
                exc,
            )
            KBStorageHelper.delete_storage(kb_path, kb_name)
            raise HTTPException(
                status_code=500,
                detail=(
                    f"Failed to persist knowledge base '{kb_name}' with backend '{backend_type_value}'. Please retry."
                ),
            ) from exc

        return KnowledgeBaseInfo(
            id=str(kb_id),
            dir_name=kb_name,
            name=kb_name.replace("_", " "),
            embedding_provider=request.embedding_provider,
            embedding_model=request.embedding_model,
            size=0,
            words=0,
            characters=0,
            chunks=0,
            avg_chunk_size=0.0,
            status="empty",

View on GitHub (pinned to 976ec789d2)

Solutions

1. Retry the create request; if it persists, verify the configured vector-store backend is reachable.

When it happens

Trigger: Occurs when persisting a new knowledge base to the configured vector backend fails; a retry may succeed.

Common situations: See trigger scenarios.

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/c1739065b8039b6d. Report an issue: GitHub.