{"record":{"id":"43bea2f655ca5b2d","repo":"langflow-ai/langflow","slug":"database-error-while-activating-version-please-tr","errorCode":null,"errorMessage":"Database error while activating version. Please try again.","messagePattern":"Database error while activating version\\. Please try again\\.","errorType":"http","errorClass":"HTTPException","httpStatus":500,"severity":"error","filePath":"src/backend/base/langflow/api/v1/flow_version.py","lineNumber":302,"sourceCode":"                    user_id=current_user.id,\n                    data=current_data,\n                    description=f\"Auto-saved before activating v{target_entry.version_number}\",\n                )\n\n            flow.data = target_data\n            flow.updated_at = datetime.now(timezone.utc)\n\n            session.add(flow)\n            await session.flush()\n    except FlowVersionError as exc:\n        raise _translate_version_error(exc) from exc\n    except IntegrityError as exc:\n        raise HTTPException(\n            status_code=409,\n            detail=\"Could not activate version — the flow was modified concurrently. Please try again.\",\n        ) from exc\n    except SQLAlchemyError as exc:\n        raise HTTPException(\n            status_code=500,\n            detail=\"Database error while activating version. Please try again.\",\n        ) from exc\n\n    await logger.adebug(\"Activated version %s (%s) for flow %s\", version_id, f\"v{target_entry.version_number}\", flow_id)\n\n    return FlowRead.model_validate(flow, from_attributes=True)\n\n\n@router.delete(\"/{version_id}\", status_code=204)\nasync def delete_version_entry(\n    flow_id: UUID,\n    version_id: UUID,\n    current_user: CurrentActiveUser,\n    session: DbSession,\n) -> None:\n    flow = await _get_user_flow(session, flow_id, current_user.id)\n    await ensure_flow_permission(","sourceCodeStart":284,"sourceCodeEnd":320,"githubUrl":"https://github.com/langflow-ai/langflow/blob/976ec789d2886a86de109c044d089d68e96c9a35/src/backend/base/langflow/api/v1/flow_version.py#L284-L320","documentation":"500 from the version-activation endpoint: a SQLAlchemyError other than IntegrityError escaped the savepoint block — connection loss, deadlock, timeout, driver error, or DDL/lock issues during flush. Distinct from the 409: this is an infrastructure/database failure, not a constraint race. The savepoint rollback means no partial activation was committed.","triggerScenarios":"Thrown at src/backend/base/langflow/api/v1/flow_version.py:302 when the library encounters an invalid state.","commonSituations":"Database restart/failover mid-request; connection pool exhaustion; long lock waits from another transaction holding the flow row; migrating the DB while the server is live.","solutions":["Check the server log for the chained SQLAlchemyError — it names the real failure (disconnected, lock wait timeout, etc.)","Verify database connectivity and pool sizing; look for other long transactions holding locks on flow/flow_version rows","Retry the activation once the database is healthy; the operation is atomic so a retry is safe"],"exampleFix":null,"handlingStrategy":"retry","validationCode":null,"typeGuard":null,"tryCatchPattern":"catch (e) {\n  if (e.response?.status === 500) return retryWithBackoff(() => activateVersion(flowId, versionId), 3);\n  throw e;\n}","preventionTips":["Activation is atomic (savepoint) so retries are always safe — build them in","Monitor DB connection pool saturation and lock waits to prevent rather than retry","Alert on repeated 500s from this endpoint; it indicates infrastructure, not client, issues"],"tags":["http-500","flow-versions","database","activate","infrastructure"],"backgroundTag":null,"analyzedSha":"976ec789d2886a86de109c044d089d68e96c9a35","analyzedAt":"2026-08-14T18:23:12.227Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}