diff --git a/docs/source/changelog.md b/docs/source/changelog.md
index ad57a296..53055022 100644
--- a/docs/source/changelog.md
+++ b/docs/source/changelog.md
@@ -7,6 +7,8 @@
   * Add support for `ExternalTableReference` to point to tables in external (i.e. not managed by `pipedag`) schemas. 
   * Remove support for `ExternalTableReference` that points to table in schema of current stage. I.e. `ExternalTableReference` can only point to tables in external schemas.
 - Fix polars import in `pyproject.toml` when using OS X with rosetta2
+- Bug fix ibm_db2 backend:
+  * input tables for SQL queries were not locked
 
 ## 0.6.10 (2024-02-29)
 - Fix bug where a `Task` that was declared lazy but provided a `Table` without a query string would always be cache valid.
diff --git a/src/pydiverse/pipedag/materialize/core.py b/src/pydiverse/pipedag/materialize/core.py
index d81d6e69..36aaf4ef 100644
--- a/src/pydiverse/pipedag/materialize/core.py
+++ b/src/pydiverse/pipedag/materialize/core.py
@@ -588,7 +588,7 @@ def _input_tables_visitor(x):
                     input_tables.append(x)
                 return x
 
-            deep_map(bound.arguments.values(), _input_tables_visitor)
+            deep_map(bound.arguments, _input_tables_visitor)
             task_context.input_tables = input_tables
 
             # Not found in cache / lazy -> Evaluate Function