apache/beam · error

invalid bigtableio.Mutation: %s

Error message

invalid bigtableio.Mutation: %s

What it means

Before applying each Mutation to Bigtable, writeFn.ProcessElement calls validateMutation; any validation failure (e.g. empty row key, missing column family, invalid column/value combination) is wrapped as "invalid bigtableio.Mutation" with the row key context in the underlying message.

Source

Thrown at sdks/go/pkg/beam/io/bigtableio/bigtable.go:169

	f.table = f.client.Open(f.TableName)
	return nil
}

func (f *writeFn) Teardown() error {
	if err := f.client.Close(); err != nil {
		return fmt.Errorf("could not close data operations client: %v", err)
	}
	return nil
}

func (f *writeFn) ProcessElement(ctx context.Context, key int, values func(*Mutation) bool) error {

	var mutation Mutation
	for values(&mutation) {

		err := validateMutation(mutation)
		if err != nil {
			return fmt.Errorf("invalid bigtableio.Mutation: %s", err)
		}

		err = f.table.Apply(ctx, mutation.RowKey, getBigtableMutation(mutation))
		if err != nil {
			return fmt.Errorf("could not apply mutation for row key='%s': %v", mutation.RowKey, err)
		}

	}

	return nil
}

type writeBatchFn struct {
	// Project is the project
	Project string `json:"project"`
	// InstanceID is the bigtable instanceID
	InstanceID string `json:"instanceId"`
	// Client is the bigtable.Client

View on GitHub (pinned to 12126d8942)

Solutions

1. Read the wrapped validateMutation message to see which field is invalid and the offending row key.
2. Filter or skip records with empty/invalid row keys before building Mutations.
3. Ensure ColumnFamily matches a family defined on the target Bigtable table.
4. Add unit tests mirroring TestMustNotBeBigtableioMutation-style validation for your DoFn output.

Example fix

// before
func toMutation(k string, v []byte) bigtableio.Mutation {
    return bigtableio.Mutation{RowKey: k, ...}
}
// after
func toMutation(k string, v []byte) (bigtableio.Mutation, error) {
    if k == "" {
        return bigtableio.Mutation{}, nil // skip
    }
    return bigtableio.Mutation{RowKey: k, ...}, nil
}

func validMutation(m bigtableio.Mutation) bool {
    return m.RowKey != "" && m.ColumnFamily != "" && m.Column != ""
}

func isValidMutation(m bigtableio.Mutation) bool {
    return validateMutation(m) == nil
}

if err := writeResult(ctx); err != nil && strings.Contains(err.Error(), "invalid bigtableio.Mutation") {
    // surface row key from message; fix producing DoFn
}

When it happens

Trigger: Emitting a bigtableio.Mutation with invalid contents — commonly an empty RowKey, empty ColumnFamily, or an empty Column qualifier — into the PCollection passed to bigtableio.Write/WriteBatch.

Common situations: Source records with missing/blank keys being mapped straight into Mutations; column family name mismatch with the table's schema; DoFn producing default-constructed Mutation values on empty input.

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

• error encoding pane %v: non-speculative index value must be
• type must be bigtableio.Mutation but is: %v
• could not create data operations client: %v
• multi-chunk stream with invalid chunk size of %d
• strictness check failed

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/86e3321d6897d9b6. Report an issue: GitHub.