fix: remove destructive vector_store.reset() from delete_all() (#4349)

mem0/memory/main.py

@@ -1047,11 +1047,10 @@ class Memory(MemoryBase):
 
         keys, encoded_ids = process_telemetry_filters(filters)
         capture_event("mem0.delete_all", self, {"keys": keys, "encoded_ids": encoded_ids, "sync_type": "sync"})
-        # delete all vector memories and reset the collections
+        # delete matching vector memories individually (do NOT reset the collection)
         memories = self.vector_store.list(filters=filters)[0]
         for memory in memories:
             self._delete_memory(memory.id)
-        self.vector_store.reset()
 
         logger.info(f"Deleted {len(memories)} memories")
 

tests/test_main.py

@@ -196,12 +196,15 @@ def test_delete_all(memory_instance, version, enable_graph):
     memory_instance.enable_graph = enable_graph
     mock_memories = [Mock(id="1"), Mock(id="2")]
     memory_instance.vector_store.list = Mock(return_value=(mock_memories, None))
+    memory_instance.vector_store.reset = Mock()
     memory_instance._delete_memory = Mock()
     memory_instance.graph.delete_all = Mock()
 
     result = memory_instance.delete_all(user_id="test_user")
 
     assert memory_instance._delete_memory.call_count == 2
+    # Ensure the collection is NOT dropped — only matched memories should be removed
+    memory_instance.vector_store.reset.assert_not_called()
 
     if enable_graph:
         memory_instance.graph.delete_all.assert_called_once_with({"user_id": "test_user"})