jaegertracing/jaeger · error

%s: %w

Error message

%s: %w

What it means

logError is the SpanWriter's uniform error funnel: it logs the failed write step (msg) with trace ID, span ID and the underlying error, then returns fmt.Errorf("%s: %w", msg, err). Callers (writeSpanToDB, writeIndexes, indexByTags) pass messages like 'failed to save service name' or 'failed to write index', so the surfaced error combines the step name with the Cassandra cause.

Solutions

1. Read the logged msg + wrapped error to identify the failing step and root Cassandra cause.
2. Retry the span write; Jaeger writes are idempotent for the same span/ID.
3. Address cluster write health: timeouts, replication, nodetool repair.
4. Check for oversized spans (huge tag payloads, max_trace/archive limits) and adjust writer config or data.

if err := writer.WriteSpan(ctx, span); err != nil {
    // err embeds the failing step ('failed to write index', etc.) plus the
    // Cassandra cause; log spanID/traceID and retry or drop per policy
    logger.Error("span write failed", zap.Error(err))
}

When it happens

Trigger: Any span write path failing: inserting into traces, writing duration/service-name/operation indexes or tag indexes when Cassandra rejects or times out the write — write timeout, unavailable, consistency failure, or oversized data.

Common situations: Cassandra write timeouts under load; batch of index writes exceeding limits; keyspace misconfiguration on a fresh deployment; too many tags creating large rows; node outages.

Related errors

• error reading dependencies from storage
• error reading operation_names from storage
• error reading probabilities from storage
• error reading from storage
• error reading service_names from storage

AI-assisted analysis of jaegertracing/jaeger@806f444784 (2026-09-01). Data as JSON: /api/errors/a65120c8bcb4f3bb. Report an issue: GitHub.

Appendix: source

Thrown at internal/storage/v1/cassandra/spanstore/writer.go:280

		var js json.RawMessage
		// poor man's string-is-a-json check shortcircuits full unmarshalling
		return strings.HasPrefix(s, "{") && json.Unmarshal([]byte(s), &js) == nil
	}

	return len(tag.TagKey) < maximumTagKeyOrValueSize &&
		len(tag.TagValue) < maximumTagKeyOrValueSize &&
		utf8.ValidString(tag.TagValue) &&
		utf8.ValidString(tag.TagKey) &&
		!isJSON(tag.TagValue)
}

func (*SpanWriter) logError(span *dbmodel.Span, err error, msg string, logger *zap.Logger) error {
	logger.
		With(zap.String("trace_id", span.TraceID.String())).
		With(zap.Int64("span_id", span.SpanID)).
		With(zap.Error(err)).
		Error(msg)
	return fmt.Errorf("%s: %w", msg, err)
}

func (s *SpanWriter) saveServiceNameAndOperationName(operation dbmodel.Operation) error {
	if err := s.serviceNamesWriter(operation.ServiceName); err != nil {
		return err
	}
	return s.operationNamesWriter(operation)
}

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