diff --git a/go.mod b/go.mod
index b35eafe5..f9bf7e42 100644
--- a/go.mod
+++ b/go.mod
@@ -124,5 +124,3 @@ require (
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	sigs.k8s.io/yaml v1.6.0 // indirect
 )
-
-replace github.com/ClusterCockpit/cc-lib/v2 => ../cc-lib
diff --git a/go.sum b/go.sum
index d5bbe045..509c659c 100644
--- a/go.sum
+++ b/go.sum
@@ -4,6 +4,8 @@ github.com/99designs/gqlgen v0.17.85 h1:EkGx3U2FDcxQm8YDLQSpXIAVmpDyZ3IcBMOJi2nH
 github.com/99designs/gqlgen v0.17.85/go.mod h1:yvs8s0bkQlRfqg03YXr3eR4OQUowVhODT/tHzCXnbOU=
 github.com/Azure/go-ntlmssp v0.0.0-20221128193559-754e69321358 h1:mFRzDkZVAjdal+s7s0MwaRv9igoPqLRdzOLzw/8Xvq8=
 github.com/Azure/go-ntlmssp v0.0.0-20221128193559-754e69321358/go.mod h1:chxPXzSsl7ZWRAuOIE23GDNzjWuZquvFlgA8xmpunjU=
+github.com/ClusterCockpit/cc-lib/v2 v2.4.0 h1:OnZlvqSatg7yCQ2NtSR7AddpUVSiuSMZ8scF1a7nfOk=
+github.com/ClusterCockpit/cc-lib/v2 v2.4.0/go.mod h1:JuxMAuEOaLLNEnnL9U3ejha8kMvsSatLdKPZEgJw6iw=
 github.com/DATA-DOG/go-sqlmock v1.5.2 h1:OcvFkGmslmlZibjAjaHm3L//6LiuBgolP7OputlJIzU=
 github.com/DATA-DOG/go-sqlmock v1.5.2/go.mod h1:88MAG/4G7SMwSE3CeA0ZKzrT5CiOU3OJ+JlNzwDqpNU=
 github.com/KyleBanks/depth v1.2.1 h1:5h8fQADFrWtarTdtDudMmGsC7GPbOAu6RVB3ffsVFHc=
diff --git a/internal/repository/node.go b/internal/repository/node.go
index a746182b..08a694c6 100644
--- a/internal/repository/node.go
+++ b/internal/repository/node.go
@@ -254,7 +254,7 @@ func (r *NodeRepository) FindNodeStatesBefore(cutoff int64) ([]NodeStateWithNode
 		From("node_state").
 		Join("node ON node_state.node_id = node.id").
 		Where(sq.Lt{"node_state.time_stamp": cutoff}).
-		Where("node_state.id NOT IN (SELECT MAX(id) FROM node_state GROUP BY node_id)").
+		Where("node_state.id NOT IN (SELECT ns2.id FROM node_state ns2 WHERE ns2.time_stamp = (SELECT MAX(ns3.time_stamp) FROM node_state ns3 WHERE ns3.node_id = ns2.node_id))").
 		OrderBy("node_state.time_stamp ASC").
 		RunWith(r.DB).Query()
 	if err != nil {
@@ -278,10 +278,14 @@ func (r *NodeRepository) FindNodeStatesBefore(cutoff int64) ([]NodeStateWithNode
 }
 
 // DeleteNodeStatesBefore removes node_state rows with time_stamp < cutoff,
-// but always preserves the latest row per node_id.
+// but always preserves the row with the latest timestamp per node_id.
 func (r *NodeRepository) DeleteNodeStatesBefore(cutoff int64) (int64, error) {
 	res, err := r.DB.Exec(
-		`DELETE FROM node_state WHERE time_stamp < ? AND id NOT IN (SELECT MAX(id) FROM node_state GROUP BY node_id)`,
+		`DELETE FROM node_state WHERE time_stamp < ?
+		 AND id NOT IN (
+		   SELECT id FROM node_state ns2
+		   WHERE ns2.time_stamp = (SELECT MAX(ns3.time_stamp) FROM node_state ns3 WHERE ns3.node_id = ns2.node_id)
+		 )`,
 		cutoff,
 	)
 	if err != nil {
diff --git a/internal/repository/node_test.go b/internal/repository/node_test.go
index 4286ab34..d1e86b9a 100644
--- a/internal/repository/node_test.go
+++ b/internal/repository/node_test.go
@@ -156,8 +156,12 @@ func nodeTestSetup(t *testing.T) {
 func TestUpdateNodeState(t *testing.T) {
 	nodeTestSetup(t)
 
+	repo := GetNodeRepository()
+	now := time.Now().Unix()
+
 	nodeState := schema.NodeStateDB{
-		TimeStamp: time.Now().Unix(), NodeState: "allocated",
+		TimeStamp:       now,
+		NodeState:       "allocated",
 		CpusAllocated:   72,
 		MemoryAllocated: 480,
 		GpusAllocated:   0,
@@ -165,18 +169,152 @@ func TestUpdateNodeState(t *testing.T) {
 		JobsRunning:     1,
 	}
 
-	repo := GetNodeRepository()
 	err := repo.UpdateNodeState("host124", "testcluster", &nodeState)
 	if err != nil {
-		return
+		t.Fatal(err)
 	}
 
 	node, err := repo.GetNode("host124", "testcluster", false)
 	if err != nil {
-		return
+		t.Fatal(err)
 	}
 
 	if node.NodeState != "allocated" {
 		t.Errorf("wrong node state\ngot: %s \nwant: allocated ", node.NodeState)
 	}
+
+	t.Run("FindBeforeEmpty", func(t *testing.T) {
+		// Only the current-timestamp row exists, so nothing should be found before now
+		rows, err := repo.FindNodeStatesBefore(now)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(rows) != 0 {
+			t.Errorf("expected 0 rows, got %d", len(rows))
+		}
+	})
+
+	t.Run("DeleteOldRows", func(t *testing.T) {
+		// Insert 2 more old rows for host124
+		for i, ts := range []int64{now - 7200, now - 3600} {
+			ns := schema.NodeStateDB{
+				TimeStamp:       ts,
+				NodeState:       "allocated",
+				HealthState:     schema.MonitoringStateFull,
+				CpusAllocated:   72,
+				MemoryAllocated: 480,
+				JobsRunning:     i,
+			}
+			if err := repo.UpdateNodeState("host124", "testcluster", &ns); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		// Delete rows older than 30 minutes
+		cutoff := now - 1800
+		cnt, err := repo.DeleteNodeStatesBefore(cutoff)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Should delete the 2 old rows
+		if cnt != 2 {
+			t.Errorf("expected 2 deleted rows, got %d", cnt)
+		}
+
+		// Latest row should still exist
+		node, err := repo.GetNode("host124", "testcluster", false)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if node.NodeState != "allocated" {
+			t.Errorf("expected node state 'allocated', got %s", node.NodeState)
+		}
+	})
+
+	t.Run("PreservesLatestPerNode", func(t *testing.T) {
+		// Insert a single old row for host125 — it's the latest per node so it must survive
+		ns := schema.NodeStateDB{
+			TimeStamp:       now - 7200,
+			NodeState:       "idle",
+			HealthState:     schema.MonitoringStateFull,
+			CpusAllocated:   0,
+			MemoryAllocated: 0,
+			JobsRunning:     0,
+		}
+		if err := repo.UpdateNodeState("host125", "testcluster", &ns); err != nil {
+			t.Fatal(err)
+		}
+
+		// Delete everything older than now — the latest per node should be preserved
+		_, err := repo.DeleteNodeStatesBefore(now)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// The latest row for host125 must still exist
+		node, err := repo.GetNode("host125", "testcluster", false)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if node.NodeState != "idle" {
+			t.Errorf("expected node state 'idle', got %s", node.NodeState)
+		}
+
+		// Verify exactly 1 row remains for host125
+		var countAfter int
+		if err := repo.DB.QueryRow(
+			"SELECT COUNT(*) FROM node_state WHERE node_id = (SELECT id FROM node WHERE hostname = 'host125')").
+			Scan(&countAfter); err != nil {
+			t.Fatal(err)
+		}
+		if countAfter != 1 {
+			t.Errorf("expected 1 row remaining for host125, got %d", countAfter)
+		}
+	})
+
+	t.Run("FindBeforeWithJoin", func(t *testing.T) {
+		// Insert old and current rows for host123
+		for _, ts := range []int64{now - 7200, now} {
+			ns := schema.NodeStateDB{
+				TimeStamp:       ts,
+				NodeState:       "allocated",
+				HealthState:     schema.MonitoringStateFull,
+				CpusAllocated:   8,
+				MemoryAllocated: 1024,
+				GpusAllocated:   1,
+				JobsRunning:     1,
+			}
+			if err := repo.UpdateNodeState("host123", "testcluster", &ns); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		// Find rows older than 30 minutes, excluding latest per node
+		cutoff := now - 1800
+		rows, err := repo.FindNodeStatesBefore(cutoff)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Should find the old host123 row
+		found := false
+		for _, row := range rows {
+			if row.Hostname == "host123" && row.TimeStamp == now-7200 {
+				found = true
+				if row.Cluster != "testcluster" {
+					t.Errorf("expected cluster 'testcluster', got %s", row.Cluster)
+				}
+				if row.SubCluster != "sc1" {
+					t.Errorf("expected subcluster 'sc1', got %s", row.SubCluster)
+				}
+				if row.CpusAllocated != 8 {
+					t.Errorf("expected cpus_allocated 8, got %d", row.CpusAllocated)
+				}
+			}
+		}
+		if !found {
+			t.Errorf("expected to find old host123 row among %d results", len(rows))
+		}
+	})
 }