diff --git a/cmd/cc-backend/main.go b/cmd/cc-backend/main.go
index 12aa9104..9b8cd1b0 100644
--- a/cmd/cc-backend/main.go
+++ b/cmd/cc-backend/main.go
@@ -320,8 +320,13 @@ func runServer(ctx context.Context) error {
 	mscfg := ccconf.GetPackageConfig("metric-store")
 	if mscfg != nil {
 		metricstore.Init(mscfg, &wg)
+
+		// Inject repository as NodeProvider to break import cycle
+		ms := metricstore.GetMemoryStore()
+		jobRepo := repository.GetJobRepository()
+		ms.SetNodeProvider(jobRepo)
 	} else {
-		cclog.Debug("Metric store configuration not found, skipping metricstore initialization")
+		return fmt.Errorf("missing metricstore configuration")
 	}
 
 	// Start archiver and task manager
diff --git a/internal/metricstore/metricstore.go b/internal/metricstore/metricstore.go
index 7c17cd88..37028654 100644
--- a/internal/metricstore/metricstore.go
+++ b/internal/metricstore/metricstore.go
@@ -45,6 +45,15 @@ var (
 	shutdownFunc context.CancelFunc
 )
 
+// NodeProvider provides information about nodes currently in use by running jobs.
+// This interface allows metricstore to query job information without directly
+// depending on the repository package, breaking the import cycle.
+type NodeProvider interface {
+	// GetUsedNodes returns a map of cluster names to sorted lists of unique hostnames
+	// that are currently in use by jobs that started before the given timestamp.
+	GetUsedNodes(ts int64) (map[string][]string, error)
+}
+
 type Metric struct {
 	Name         string
 	Value        schema.Float
@@ -52,8 +61,9 @@ type Metric struct {
 }
 
 type MemoryStore struct {
-	Metrics map[string]MetricConfig
-	root    Level
+	Metrics      map[string]MetricConfig
+	root         Level
+	nodeProvider NodeProvider // Injected dependency for querying running jobs
 }
 
 func Init(rawConfig json.RawMessage, wg *sync.WaitGroup) {
@@ -196,6 +206,14 @@ func GetMemoryStore() *MemoryStore {
 	return msInstance
 }
 
+// SetNodeProvider sets the NodeProvider implementation for the MemoryStore.
+// This must be called during initialization to provide job state information
+// for selective buffer retention during Free operations.
+// If not set, the Free function will fall back to freeing all buffers.
+func (ms *MemoryStore) SetNodeProvider(provider NodeProvider) {
+	ms.nodeProvider = provider
+}
+
 func Shutdown() {
 	if shutdownFunc != nil {
 		shutdownFunc()
@@ -263,13 +281,17 @@ func Retention(wg *sync.WaitGroup, ctx context.Context) {
 }
 
 func Free(ms *MemoryStore, t time.Time) (int, error) {
-	// jobRepo := repository.GetJobRepository()
-	// excludeSelectors, err := jobRepo.GetUsedNodes(t.Unix())
-	// if err != nil {
-	// 	return 0, err
-	// }
+	// If no NodeProvider is configured, free all buffers older than t
+	if ms.nodeProvider == nil {
+		return ms.Free(nil, t.Unix())
+	}
 
-	excludeSelectors := make(map[string][]string, 0)
+	excludeSelectors, err := ms.nodeProvider.GetUsedNodes(t.Unix())
+	if err != nil {
+		return 0, err
+	}
+
+	// excludeSelectors := make(map[string][]string, 0)
 
 	// excludeSelectors := map[string][]string{
 	// 	"alex":  {"a0122", "a0123", "a0225"},