apache/seatunnel · error · IOException

Redis sink cannot restore writer for table %s because state

Error message

Redis sink cannot restore writer for table %s because state 0 fields %s differ from state %d fields %s

What it means

On job recovery, RedisSink.restoreWriter() compares the TableSchema of the first saved state against every other state; if any differ it throws an IOException explaining that a single writer cannot be restored from inconsistent table states. This guards against silently writing data with a mismatched schema after a savepoint/checkpoint restart or config change.

Source

Thrown at seatunnel-connectors-v2/connector-redis/src/main/java/org/apache/seatunnel/connectors/seatunnel/redis/sink/RedisSink.java:78

        return new RedisSinkWriter(tableSchema, redisParameters);
    }

    /**
     * Restores the latest writer schema. Rescaling can provide state from multiple writers, and
     * every state must contain the same schema because selecting the widest schema would restore a
     * stale definition after a drop-column event.
     */
    @Override
    public RedisSinkWriter restoreWriter(SinkWriter.Context context, List<TableSchema> states)
            throws IOException {
        if (states == null || states.isEmpty()) {
            return createWriter(context);
        }
        TableSchema restoredSchema = states.get(0);
        for (int stateIndex = 1; stateIndex < states.size(); stateIndex++) {
            TableSchema state = states.get(stateIndex);
            if (!restoredSchema.equals(state)) {
                throw new IOException(
                        String.format(
                                "Redis sink cannot restore writer for table %s because state 0 fields %s differ from state %d fields %s",
                                catalogTable.getTablePath().getFullName(),
                                schemaFields(restoredSchema),
                                stateIndex,
                                schemaFields(state)));
            }
        }
        return new RedisSinkWriter(restoredSchema, redisParameters);
    }

    @Override
    public Optional<Serializer<TableSchema>> getWriterStateSerializer() {
        return Optional.of(new DefaultSerializer<>());
    }

    @Override
    public Optional<CatalogTable> getWriteCatalogTable() {

View on GitHub (pinned to cf67b549a7)

Solutions

  1. Restore from a savepoint taken with the same table schema, or discard the old savepoint and start the job fresh (losing in-flight state).
  2. Revert schema changes (column names/types/order) so they match the saved state exactly.
  3. If schemas legitimately differ per branch, split into separate sink/table configurations instead of merging into one sink state.
  4. Verify the restored schema by printing schemaFields of state 0 and the diverging state from the message and aligning them.

Example fix

// before
# schema changed: added column age
schema = { fields { id int, name string, age int } }
// after
# match original schema, or start fresh without old savepoint
schema = { fields { id int, name string } }
Defensive patterns

Strategy: try-catch

Try / catch

try {
    sink.restoreWriter(context, states);
} catch (IOException e) {
    // schema drift detected: align schema or discard old savepoint and restart
}

Prevention

When it happens

Trigger: restoreWriter() is called with multiple saved TableSchema states where state N (N>=1) does not equal state 0 — typically because the sink's catalog table schema (columns/types) was changed between the savepoint and the restore, producing divergent field lists.

Common situations: Altering column names/types in the SeaTunnel SQL/config and resuming from an old savepoint; multi-upstream pipelines whose branches produced different schemas; or version upgrades that changed schema serialization.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/7132cd593cbe9d47. Report an issue: GitHub.