SigNoz/signoz · error

error while executing query: %s

Error message

error while executing query: %s

What it means

In the metric attribute-keys lookup, the db.Query with parameters (AggregateAttribute, PastDayRoundOff, %SearchText%) failed to execute. This query lists tag keys associated with a chosen metric over the last day; failure means ClickHouse rejected or could not run it, with the raw error embedded in %s.

Source

Thrown at pkg/query-service/app/clickhouseReader/reader.go:3121

	var err error
	var rows driver.Rows
	var response v3.FilterAttributeKeyResponse

	reductionEnabled := r.fl.BooleanOrEmpty(ctx, flagger.FeatureEnableMetricsReduction, featuretypes.NewFlaggerEvaluationContext(orgID))

	// skips the internal attributes i.e attributes starting with __
	if reductionEnabled {
		query = fmt.Sprintf("SELECT arrayJoin(tagKeys) AS distinctTagKey FROM (SELECT JSONExtractKeys(labels) AS tagKeys FROM %s.%s WHERE metric_name=$1 AND unix_milli >= $2 GROUP BY tagKeys UNION ALL SELECT JSONExtractKeys(labels) AS tagKeys FROM %s.%s WHERE metric_name=$1 AND unix_milli >= $2 GROUP BY tagKeys) WHERE distinctTagKey ILIKE $3 AND distinctTagKey NOT LIKE '\\_\\_%%' GROUP BY distinctTagKey", signozMetricDBName, signozTSTableNameV41Day, signozMetricDBName, signozTSTableNameV4Reduced)
	} else {
		query = fmt.Sprintf("SELECT arrayJoin(tagKeys) AS distinctTagKey FROM (SELECT JSONExtractKeys(labels) AS tagKeys FROM %s.%s WHERE metric_name=$1 AND unix_milli >= $2 GROUP BY tagKeys) WHERE distinctTagKey ILIKE $3 AND distinctTagKey NOT LIKE '\\_\\_%%' GROUP BY distinctTagKey", signozMetricDBName, signozTSTableNameV41Day)
	}
	if req.Limit != 0 {
		query = query + fmt.Sprintf(" LIMIT %d;", req.Limit)
	}
	rows, err = r.db.Query(ctx, query, req.AggregateAttribute, common.PastDayRoundOff(), fmt.Sprintf("%%%s%%", req.SearchText))
	if err != nil {
		r.logger.Error("Error while executing query", errorsV2.Attr(err))
		return nil, fmt.Errorf("error while executing query: %s", err.Error())
	}
	defer rows.Close()

	var attributeKey string
	for rows.Next() {
		if err := rows.Scan(&attributeKey); err != nil {
			return nil, fmt.Errorf("error while scanning rows: %s", err.Error())
		}
		key := v3.AttributeKey{
			Key:      attributeKey,
			DataType: v3.AttributeKeyDataTypeString, // https://github.com/OpenObservability/OpenMetrics/blob/main/proto/openmetrics_data_model.proto#L64-L72.
			Type:     v3.AttributeKeyTypeTag,
			IsColumn: false,
		}
		response.AttributeKeys = append(response.AttributeKeys, key)
	}

	return &response, nil

View on GitHub (pinned to 5069bf80b0)

Solutions

1. Inspect the %s suffix for the underlying ClickHouse error
2. Verify the metrics attribute tables exist and have data within the last day (the query filters on PastDayRoundOff)
3. Sanitize/limit SearchText length on the API boundary
4. Retry when ClickHouse is healthy; the query is read-only

// validate inputs before calling
if req.AggregateAttribute == "" || len(req.SearchText) > 100 { return empty, nil }

if err != nil {
  if strings.Contains(err.Error(), "UNKNOWN_TABLE") { return emptyKeys(), nil }
  if isTransientClickhouseErr(err) { return retry(ctx) }
  return nil, err
}

When it happens

Trigger: Building a query-builder filter UI for metrics: user selects an aggregate attribute and the backend fetches available tag keys, but the time_series/attributes table is missing, unreachable, or the parameter binding fails.

Common situations: Fresh clusters with no metric data; signoz_metrics schema not created; special characters in SearchText breaking the LIKE pattern; ClickHouse overload.

Related errors

• error while executing metric name query: %s
• error while executing meter name query: %s
• error while scanning rows: %s
• CodeLicenseUnavailable
• CodeForbidden

AI-assisted analysis of SigNoz/signoz@5069bf80b0 (2026-08-28). Data as JSON: /api/errors/baf2155ef8f0935f. Report an issue: GitHub.