Fix primary key behaviour in bulk_update

Suppose you have a model class with a primary key.

Base = declarative_base()
class User(Base):
  id = Column(BigInteger, primary_key=True)
  name = Column(String)

Previously, running
`bulk_update_mappings(User, {'id': 1, 'name': 'hello'})`
would emit the following:

```UPDATE users SET id=1, name='hello' WHERE id=1```

This is contrary to the stated behaviour, where primary keys are omitted
from the SET clause. Furthermore, this behaviour is harmful, as it
can cause the db engine to lock over-aggresively (at least in Postgres).

With this change, the emitted SQL is:

```UPDATE users SET name='hello' WHERE id=1```

diff --git a/lib/sqlalchemy/orm/persistence.py b/lib/sqlalchemy/orm/persistence.py
index b429aa4c171b461cff6712c61082826ea8bb2284..254d3bf09a65cf2cac374133f39cd3220d251622 100644 (file)
--- a/lib/sqlalchemy/orm/persistence.py
+++ b/lib/sqlalchemy/orm/persistence.py
@@ -472,12 +472,11 @@ def _collect_update_commands(
             continue
 
         if bulk:
-            pk_params = dict(
-                (propkey_to_col[propkey]._label, state_dict.get(propkey))
-                for propkey in
-                set(propkey_to_col).
-                intersection(mapper._pk_keys_by_table[table])
-            )
+            pk_params = {}
+            for propkey in set(propkey_to_col).intersection(mapper._pk_keys_by_table[table]):
+              col = propkey_to_col[propkey]
+              pk_params[col._label] = state_dict.get(propkey)
+              params.pop(col.key, None)
         else:
             pk_params = {}
             for col in pks:

diff --git a/test/orm/test_bulk.py b/test/orm/test_bulk.py
index e27d3b73c84f30eac05ba505843bb9a0ff543f86..1e0a735c7616bbb53d2c44c1527c7789880b2984 100644 (file)
--- a/test/orm/test_bulk.py
+++ b/test/orm/test_bulk.py
@@ -96,11 +96,41 @@ class BulkInsertUpdateTest(BulkTest, _fixtures.FixtureTest):
 
         asserter.assert_(
             CompiledSQL(
-                "UPDATE users SET id=:id, name=:name WHERE "
+                "UPDATE users SET name=:name WHERE "
                 "users.id = :users_id",
-                [{'users_id': 1, 'id': 1, 'name': 'u1new'},
-                 {'users_id': 2, 'id': 2, 'name': 'u2'},
-                 {'users_id': 3, 'id': 3, 'name': 'u3new'}]
+                [{'users_id': 1, 'name': 'u1new'},
+                 {'users_id': 2, 'name': 'u2'},
+                 {'users_id': 3, 'name': 'u3new'}]
+            )
+        )
+
+    def test_bulk_update(self):
+        User, = self.classes("User",)
+
+        s = Session(expire_on_commit=False)
+        objects = [
+            User(name="u1"),
+            User(name="u2"),
+            User(name="u3")
+        ]
+        s.add_all(objects)
+        s.commit()
+
+        s = Session()
+        with self.sql_execution_asserter() as asserter:
+            s.bulk_update_mappings(
+                User,
+                [{'id': 1, 'name': 'u1new'},
+                 {'id': 2, 'name': 'u2'},
+                 {'id': 3, 'name': 'u3new'}]
+            )
+
+        asserter.assert_(
+            CompiledSQL(
+                "UPDATE users SET name=:name WHERE users.id = :users_id",
+                [{'users_id': 1, 'name': 'u1new'},
+                 {'users_id': 2, 'name': 'u2'},
+                 {'users_id': 3, 'name': 'u3new'}]
             )
         )