feat: add update_rows parameter to sync_trigger()

CHANGES.rst

@@ -10,6 +10,8 @@ Unreleased
 - Add support for PostgreSQL 16
 - Allow specifying schema in ``drop_trigger`` and ``sync_trigger`` (#95, pull
   request by @acarapetis)
+- Add ``update_rows`` parameter to ``sync_trigger`` (#76, pull request by
+  @scribu)
 
 2.0.0 (2023-08-28)
 ^^^^^^^^^^^^^^^^^^

sqlalchemy_searchable/__init__.py

@@ -296,6 +296,7 @@ def sync_trigger(
     metadata=None,
     options=None,
     schema=None,
+    update_rows=True,
 ):
     """Synchronize the search trigger and trigger function for the given table and
     search vector column. Internally, this function executes the following SQL
@@ -380,6 +381,9 @@ def hstore_vectorizer(column):
         Table. If None is given, then a new MetaData object is initialized within
         this function.
     :param options: Dictionary of configuration options
+    :param update_rows:
+        If set to False, the values in the vector column will remain unchanged
+        until one of the indexed columns is updated.
     """
     if metadata is None:
         metadata = sa.MetaData()
@@ -402,10 +406,12 @@ def hstore_vectorizer(column):
     ]
     for class_ in classes:
         conn.execute(class_(**params))
-    update_sql = table.update().values(
-        {indexed_columns[0]: sa.text(indexed_columns[0])}
-    )
-    conn.execute(update_sql)
+
+    if update_rows:
+        update_sql = table.update().values(
+            {indexed_columns[0]: sa.text(indexed_columns[0])}
+        )
+        conn.execute(update_sql)
 
 
 def drop_trigger(

tests/test_sync_trigger.py

@@ -126,6 +126,35 @@ def test_updates_column_values(self, engine, ts_vector_options):
             vector = conn.execute(text("SELECT search_vector FROM article")).scalar()
         assert vector == "'content':2"
 
+    def test_does_not_update_column_values_when_updating_rows_disabled(
+        self, engine, ts_vector_options
+    ):
+        with engine.begin() as conn:
+            sync_trigger(
+                conn,
+                "article",
+                "search_vector",
+                ["name", "content"],
+                options=ts_vector_options,
+            )
+            conn.execute(
+                text(
+                    """INSERT INTO article (name, content)
+                    VALUES ('some name', 'some content')"""
+                )
+            )
+            conn.execute(text("ALTER TABLE article DROP COLUMN name"))
+            sync_trigger(
+                conn,
+                "article",
+                "search_vector",
+                ["content"],
+                options=ts_vector_options,
+                update_rows=False,
+            )
+            vector = conn.execute(text("SELECT search_vector FROM article")).scalar()
+        assert vector == "'content':4 'name':2"
+
     def test_custom_vectorizers(sel, Base, engine, session, ts_vector_options):
         articles = sa.Table(
             "article",