diff --git a/backend/internal/repository/ops_repo_trends.go b/backend/internal/repository/ops_repo_trends.go
index 61b5ad64..e4ac96d3 100644
--- a/backend/internal/repository/ops_repo_trends.go
+++ b/backend/internal/repository/ops_repo_trends.go
@@ -265,7 +265,7 @@ LIMIT $4`
 	if err != nil {
 		return nil, err
 	}
-	defer rows.Close()
+	defer func() { _ = rows.Close() }()
 
 	items := make([]*service.OpsThroughputGroupBreakdownItem, 0, limit)
 	for rows.Next() {
@@ -431,7 +431,7 @@ ORDER BY 1 ASC`
 	if err != nil {
 		return nil, err
 	}
-	defer rows.Close()
+	defer func() { _ = rows.Close() }()
 
 	points := make([]*service.OpsErrorTrendPoint, 0, 256)
 	for rows.Next() {
@@ -542,7 +542,7 @@ LIMIT 20`
 	if err != nil {
 		return nil, err
 	}
-	defer rows.Close()
+	defer func() { _ = rows.Close() }()
 
 	items := make([]*service.OpsErrorDistributionItem, 0, 16)
 	var total int64
diff --git a/backend/internal/service/ops_settings.go b/backend/internal/service/ops_settings.go
index 00db8e99..fbf8f069 100644
--- a/backend/internal/service/ops_settings.go
+++ b/backend/internal/service/ops_settings.go
@@ -359,9 +359,9 @@ func (s *OpsService) UpdateOpsAlertRuntimeSettings(ctx context.Context, cfg *Ops
 func defaultOpsAdvancedSettings() *OpsAdvancedSettings {
 	return &OpsAdvancedSettings{
 		DataRetention: OpsDataRetentionSettings{
-			CleanupEnabled:            false,
-			CleanupSchedule:           "0 2 * * *",
-			ErrorLogRetentionDays:     30,
+			CleanupEnabled:             false,
+			CleanupSchedule:            "0 2 * * *",
+			ErrorLogRetentionDays:      30,
 			MinuteMetricsRetentionDays: 30,
 			HourlyMetricsRetentionDays: 30,
 		},
@@ -463,4 +463,3 @@ func (s *OpsService) UpdateOpsAdvancedSettings(ctx context.Context, cfg *OpsAdva
 	_ = json.Unmarshal(raw, updated)
 	return updated, nil
 }
-
diff --git a/backend/internal/service/ops_settings_models.go b/backend/internal/service/ops_settings_models.go
index 52a9db66..7d9a823c 100644
--- a/backend/internal/service/ops_settings_models.go
+++ b/backend/internal/service/ops_settings_models.go
@@ -75,14 +75,13 @@ type OpsAdvancedSettings struct {
 }
 
 type OpsDataRetentionSettings struct {
-	CleanupEnabled            bool   `json:"cleanup_enabled"`
-	CleanupSchedule           string `json:"cleanup_schedule"`
-	ErrorLogRetentionDays     int    `json:"error_log_retention_days"`
-	MinuteMetricsRetentionDays int   `json:"minute_metrics_retention_days"`
-	HourlyMetricsRetentionDays int   `json:"hourly_metrics_retention_days"`
+	CleanupEnabled             bool   `json:"cleanup_enabled"`
+	CleanupSchedule            string `json:"cleanup_schedule"`
+	ErrorLogRetentionDays      int    `json:"error_log_retention_days"`
+	MinuteMetricsRetentionDays int    `json:"minute_metrics_retention_days"`
+	HourlyMetricsRetentionDays int    `json:"hourly_metrics_retention_days"`
 }
 
 type OpsAggregationSettings struct {
 	AggregationEnabled bool `json:"aggregation_enabled"`
 }
-
diff --git a/backend/internal/service/ops_trends.go b/backend/internal/service/ops_trends.go
index 9237544c..ec55c6ce 100644
--- a/backend/internal/service/ops_trends.go
+++ b/backend/internal/service/ops_trends.go
@@ -24,4 +24,3 @@ func (s *OpsService) GetThroughputTrend(ctx context.Context, filter *OpsDashboar
 	}
 	return s.opsRepo.GetThroughputTrend(ctx, filter, bucketSeconds)
 }
-