risingwavelabs/risingwave · error

the streaming job shouldn't have an upstream fragment, job_t

Error message

the streaming job shouldn't have an upstream fragment, job_type: {:?}

What it means

For streaming jobs of type Source or Table, the graph builder expects the job to have no upstream fragment in this replacement/edge-building path. If an upstream fragment is present for such a job type, the builder bails. This is a structural check that source- and table-type jobs never receive an upstream edge here.

Source

Thrown at src/meta/src/stream/stream_graph/fragment.rs:1885

                                        downstream_fragment_id: id,
                                    },
                                    // We always use `NoShuffle` for the exchange between the upstream
                                    // `Source` and the downstream `StreamScan` of the new MV.
                                    dispatch_strategy: DispatchStrategy {
                                        r#type: DispatcherType::NoShuffle as _,
                                        dist_key_indices: vec![], // not used for `NoShuffle`
                                        output_mapping: Some(output_mapping),
                                    },
                                }
                            } else {
                                bail!(
                                    "the upstream fragment should be a MView or Source, got fragment type: {:b}",
                                    upstream_fragment.fragment_type_mask
                                )
                            }
                        }
                        StreamingJobType::Source | StreamingJobType::Table(_) => {
                            bail!(
                                "the streaming job shouldn't have an upstream fragment, job_type: {:?}",
                                job_type
                            )
                        }
                    };

                    // put the edge into the extra edges
                    extra_downstreams
                        .entry(upstream_root_fragment_id)
                        .or_insert_with(HashMap::new)
                        .try_insert(id, edge.clone())
                        .unwrap();
                    extra_upstreams
                        .entry(id)
                        .or_insert_with(HashMap::new)
                        .try_insert(upstream_root_fragment_id, edge)
                        .unwrap();
                }

View on GitHub (pinned to 6469eb736d)

Solutions

1. Verify the streaming job's type metadata: a Source/Table job should not carry an upstream fragment here; fix the replacement plan generation.
2. If this is a CREATE TABLE with a connector, ensure no upstream fragment id was mistakenly attached to the job.
3. If triggered by normal DDL, capture the job type and fragment metadata and file a bug; try recreating the job as a workaround.

Example fix

null

if matches!(job_type, StreamingJobType::Source | StreamingJobType::Table(_)) && upstream_fragment.is_some() {
    return Err("Source/Table jobs must not have an upstream fragment here");
}

fn requires_no_upstream(job_type: &StreamingJobType) -> bool {
    matches!(job_type, StreamingJobType::Source | StreamingJobType::Table(_))
}

When it happens

Trigger: Building a replacement graph for a `StreamingJobType::Source` or `StreamingJobType::Table(_)` job while the code path finds a non-empty upstream fragment for it, hitting the bail in the match arm.

Common situations: Schema-change/replacement plan construction where the job definition unexpectedly retains an upstream edge; bugs in replacement plan generation or hand-edited/incorrect job metadata.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• table_fragment does not exist: id={0}
• downstream relation missing for {} -> {}
• snapshot backfill epoch set again: {} {} {}
• the upstream fragment should be a MView or Source, got fragm
• graph is not a DAG

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/90ed47eb9a22a11f. Report an issue: GitHub.