thanos-io/thanos · error

create results cache middleware

Error message

create results cache middleware

What it means

newQueryRangeTripperware builds the results-cache middleware for query_range endpoints by calling queryrange.NewResultsCacheMiddleware. If that construction fails (invalid cache backend config, extractor/codec issues), the error is wrapped with 'create results cache middleware'. Startup of the query-frontend aborts.

Solutions

1. Read the wrapped inner error from NewResultsCacheMiddleware for the specific backend problem
2. Fix the query_range results_cache backend configuration (addresses, client timeouts, provider options)
3. Temporarily disable the query_range cache (remove results_cache block) to confirm the rest of the tripperware starts
4. Ensure all cache client dependencies (memcached/redis endpoints, DNS records) are reachable and correctly formatted

Example fix

// before
query_range:
  results_cache:
    backend: redis
    redis:
      # endpoints empty
// after
query_range:
  results_cache:
    backend: redis
    redis:
      endpoints: [redis:6379]
      ttl: 12h

if err := cfg.ResultsCacheConfig.Validate(querier.Config{}); err != nil {
    return fmt.Errorf("query range cache config invalid: %w", err)
}

func cacheEnabled(c Config) bool { return c.ResultsCacheConfig != nil }

tw, err := NewTripperware(config, ...
if err != nil && strings.Contains(err.Error(), "create results cache middleware") {
    log.Fatalf("fix query_range results_cache backend: %v", err)
}

When it happens

Trigger: NewTripperware -> newQueryRangeTripperware with caching enabled; queryrange.NewResultsCacheMiddleware returns an error because the ResultsCacheConfig (backend selection, memcached/redis client settings) is invalid or its client cannot be built.

Common situations: Cache backend configured with unsupported/invalid options; memcached client config errors (bad addresses, invalid timeouts); passing an unregistered registerer or nil dependency in custom builds; cache config validated at Validate time but backend client construction still failing.

Related errors

• parsing config YAML file
• marshal content of cache backend configuration
• response cache with type
• invalid ResultsCache config for labels tripperware
• initialize query range limits

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/8c8c971ccb50d261. Report an issue: GitHub.

Appendix: source

Thrown at pkg/queryfrontend/roundtrip.go:229

			queryRangeMiddleware,
			PromQLShardingMiddleware(analyzer, numShards, limits, codec, reg),
		)
	}

	if config.ResultsCacheConfig != nil {
		queryCacheMiddleware, _, err := queryrange.NewResultsCacheMiddleware(
			logger,
			*config.ResultsCacheConfig,
			newThanosCacheKeyGenerator(),
			limits,
			codec,
			queryrange.PrometheusResponseExtractor{},
			nil,
			shouldCache,
			reg,
		)
		if err != nil {
			return nil, errors.Wrap(err, "create results cache middleware")
		}

		queryRangeMiddleware = append(
			queryRangeMiddleware,
			queryrange.InstrumentMiddleware("results_cache", m),
			queryCacheMiddleware,
		)
	}

	if config.MaxRetries > 0 {
		queryRangeMiddleware = append(
			queryRangeMiddleware,
			queryrange.InstrumentMiddleware("retry", m),
			queryrange.NewRetryMiddleware(logger, config.MaxRetries, queryrange.NewRetryMiddlewareMetrics(reg)),
		)
	}

	return func(next http.RoundTripper) http.RoundTripper {

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