diff --git a/graph/Graph.cc b/graph/Graph.cc
index d30c464c..b3f428d1 100644
--- a/graph/Graph.cc
+++ b/graph/Graph.cc
@@ -660,12 +660,48 @@ Graph::prevPaths(Vertex *vertex) const
   return prev_paths_.pointer(vertex->prevPaths());
 }
 
+void
+Graph::deletePrevPaths(Vertex *vertex,
+                       uint32_t count)
+{
+  if (vertex->prevPaths() != object_id_null) {
+    {
+      LockGuard lock(prev_paths_lock_);
+      prev_paths_.destroy(vertex->prevPaths(), count);
+    }
+    vertex->setPrevPaths(object_id_null);
+  }
+}
+
 void
 Graph::clearPrevPaths()
 {
   prev_paths_.clear();
 }
 
+// No locks.
+void
+Graph::deletePaths(Vertex *vertex,
+                   uint32_t count)
+{
+  if (vertex->arrivals() != arrival_null) {
+    arrivals_.destroy(vertex->arrivals(), count);
+    vertex->setArrivals(arrival_null);
+  }
+  if (vertex->requireds() != arrival_null) {
+    requireds_.destroy(vertex->requireds(), count);
+    vertex->setRequireds(arrival_null);
+  }
+
+  if (vertex->prevPaths() != object_id_null) {
+    prev_paths_.destroy(vertex->prevPaths(), count);
+    vertex->setPrevPaths(object_id_null);
+  }
+
+  vertex->tag_group_index_ = tag_group_index_max;
+  vertex->crpr_path_pruning_disabled_ = false;
+}
+
 ////////////////////////////////////////////////////////////////
 
 const Slew &
@@ -1245,16 +1281,6 @@ Vertex::setPrevPaths(PrevPathId prev_paths)
   prev_paths_ = prev_paths;
 }
 
-void
-Vertex::deletePaths()
-{
-  arrivals_ = arrival_null;
-  requireds_ = arrival_null;
-  prev_paths_ = prev_path_null;
-  tag_group_index_ = tag_group_index_max;
-  crpr_path_pruning_disabled_ = false;
-}
-
 LogicValue
 Vertex::simValue() const
 {
diff --git a/include/sta/Graph.hh b/include/sta/Graph.hh
index efa0637d..01b2b773 100644
--- a/include/sta/Graph.hh
+++ b/include/sta/Graph.hh
@@ -113,7 +113,13 @@ public:
   PathVertexRep *makePrevPaths(Vertex *vertex,
 			       uint32_t count);
   PathVertexRep *prevPaths(Vertex *vertex) const;
+  void deletePrevPaths(Vertex *vertex,
+                       uint32_t count);
   void clearPrevPaths();
+  // Private to Search::deletePaths1(Vertex).
+  void deletePaths(Vertex *vertex,
+                   uint32_t count);
+
   // Reported slew are the same as those in the liberty tables.
   //  reported_slews = measured_slews / slew_derate_from_library
   // Measured slews are between slew_lower_threshold and slew_upper_threshold.
@@ -333,8 +339,6 @@ public:
   // ObjectTable interface.
   ObjectIdx objectIdx() const { return object_idx_; }
   void setObjectIdx(ObjectIdx idx);
-  // private to Search.cc
-  void deletePaths();
 
   static int transitionCount() { return 2; }  // rise/fall
 
diff --git a/include/sta/Search.hh b/include/sta/Search.hh
index 69a032de..5828f7ba 100644
--- a/include/sta/Search.hh
+++ b/include/sta/Search.hh
@@ -498,6 +498,8 @@ protected:
 			     const PathAnalysisPt *path_ap);
   void deletePaths();
   void deletePaths(Vertex *vertex);
+  // Delete with incremental tns/wns update.
+  void deletePathsIncr(Vertex *vertex);
   TagGroup *findTagGroup(TagGroupBldr *group_bldr);
   void deleteFilterTags();
   void deleteFilterTagGroups();
diff --git a/search/Search.cc b/search/Search.cc
index 0aa9ac0c..ecfa8fe2 100644
--- a/search/Search.cc
+++ b/search/Search.cc
@@ -403,7 +403,7 @@ Search::deletePaths()
     VertexIterator vertex_iter(graph_);
     while (vertex_iter.hasNext()) {
       Vertex *vertex = vertex_iter.next();
-      vertex->deletePaths();
+      deletePaths(vertex);
     }
     filtered_arrivals_->clear();
     graph_->clearArrivals();
@@ -412,13 +412,24 @@ Search::deletePaths()
   }
 }
 
+// Delete with incremental tns/wns update.
 void
-Search::deletePaths(Vertex *vertex)
+Search::deletePathsIncr(Vertex *vertex)
 {
   tnsNotifyBefore(vertex);
   if (worst_slacks_)
     worst_slacks_->worstSlackNotifyBefore(vertex);
-  vertex->deletePaths();
+  deletePaths(vertex);
+}
+
+void
+Search::deletePaths(Vertex *vertex)
+{
+  TagGroup *tag_group = tagGroup(vertex);
+  if (tag_group) {
+    int arrival_count = tag_group->arrivalCount();
+    graph_->deletePaths(vertex, arrival_count);
+  }
 }
 
 ////////////////////////////////////////////////////////////////
@@ -510,7 +521,7 @@ Search::deleteFilteredArrivals()
       for (Vertex *vertex : *filtered_arrivals_) {
         if (isClock(vertex))
           clk_arrivals_valid_ = false;
-        deletePaths(vertex);
+        deletePathsIncr(vertex);
         arrivalInvalid(vertex);
         requiredInvalid(vertex);
       }
@@ -677,7 +688,7 @@ void
 Search::deleteVertexBefore(Vertex *vertex)
 {
   if (arrivals_exist_) {
-    deletePaths(vertex);
+    deletePathsIncr(vertex);
     arrival_iter_->deleteVertexBefore(vertex);
     invalid_arrivals_->erase(vertex);
     filtered_arrivals_->erase(vertex);
@@ -759,7 +770,7 @@ void
 Search::arrivalInvalidDelete(Vertex *vertex)
 {
   arrivalInvalid(vertex);
-  vertex->deletePaths();
+  deletePaths(vertex);
 }
 
 void
@@ -1457,7 +1468,7 @@ Search::seedArrival(Vertex *vertex)
       setVertexArrivals(vertex, &tag_bldr);
     }
     else {
-      deletePaths(vertex);
+      deletePathsIncr(vertex);
       if (search_adj_->searchFrom(vertex))
 	arrival_iter_->enqueueAdjacentVertices(vertex,  search_adj_);
     }
@@ -2663,7 +2674,7 @@ Search::setVertexArrivals(Vertex *vertex,
 			  TagGroupBldr *tag_bldr)
 {
   if (tag_bldr->empty())
-    deletePaths(vertex);
+    deletePathsIncr(vertex);
   else {
     TagGroup *prev_tag_group = tagGroup(vertex);
     Arrival *prev_arrivals = graph_->arrivals(vertex);
@@ -2682,7 +2693,7 @@ Search::setVertexArrivals(Vertex *vertex,
       else {
 	// Prev paths not required.
 	prev_paths = nullptr;
-	vertex->setPrevPaths(prev_path_null);
+        graph_->deletePrevPaths(vertex, arrival_count);
       }
       tag_bldr->copyArrivals(tag_group, prev_arrivals, prev_paths);
       vertex->setTagGroupIndex(tag_group->index());