diff --git a/src/datachain/query/dataset.py b/src/datachain/query/dataset.py
index 8e5251be0..caddcbe41 100644
--- a/src/datachain/query/dataset.py
+++ b/src/datachain/query/dataset.py
@@ -1438,6 +1438,7 @@ def cleanup(self) -> None:
         # This is needed to always use a new connection with all metastore and warehouse
         # implementations, as errors may close or render unusable the existing
         # connections.
+        assert len(self.temp_table_names) == len(set(self.temp_table_names))
         with self.catalog.metastore.clone(use_new_connection=True) as metastore:
             metastore.cleanup_tables(self.temp_table_names)
         with self.catalog.warehouse.clone(use_new_connection=True) as warehouse:
@@ -1531,6 +1532,7 @@ def clone(self, new_table=True) -> "Self":
         obj.steps = obj.steps.copy()
         if new_table:
             obj.table = self.get_table()
+        obj.temp_table_names = []
         return obj
 
     @detach
@@ -1870,11 +1872,11 @@ def _add_dependencies(self, dataset: "DatasetRecord", version: str):
 
     def exec(self) -> "Self":
         """Execute the query."""
+        query = self.clone()
         try:
-            query = self.clone()
             query.apply_steps()
         finally:
-            self.cleanup()
+            query.cleanup()
         return query
 
     def save(