- The string keys that are used to determine the columns impacted

for an INSERT or UPDATE are now sorted when they contribute towards
the "compiled cache" cache key.   These keys were previously not
deterministically ordered, meaning the same statement could be
cached multiple times on equivalent keys, costing both in terms of
memory as well as performance.
fixes #3165

1 files changed, 45 insertions, 3 deletions

diff --git a/test/engine/test_execute.py b/test/engine/test_execute.py
index 291aee2f3..f65168552 100644
--- a/test/engine/test_execute.py
+++ b/test/engine/test_execute.py
@@ -688,6 +688,7 @@ class CompiledCacheTest(fixtures.TestBase):
                       Column('user_id', INT, primary_key=True,
                              test_needs_autoincrement=True),
                       Column('user_name', VARCHAR(20)),
+                      Column("extra_data", VARCHAR(20))
                       )
         metadata.create_all()
 
@@ -705,12 +706,53 @@ class CompiledCacheTest(fixtures.TestBase):
         cached_conn = conn.execution_options(compiled_cache=cache)
 
         ins = users.insert()
-        cached_conn.execute(ins, {'user_name': 'u1'})
-        cached_conn.execute(ins, {'user_name': 'u2'})
-        cached_conn.execute(ins, {'user_name': 'u3'})
+        with patch.object(
+            ins, "compile",
+                Mock(side_effect=ins.compile)) as compile_mock:
+            cached_conn.execute(ins, {'user_name': 'u1'})
+            cached_conn.execute(ins, {'user_name': 'u2'})
+            cached_conn.execute(ins, {'user_name': 'u3'})
+        eq_(compile_mock.call_count, 1)
         assert len(cache) == 1
         eq_(conn.execute("select count(*) from users").scalar(), 3)
 
+    def test_keys_independent_of_ordering(self):
+        conn = testing.db.connect()
+        conn.execute(
+            users.insert(),
+            {"user_id": 1, "user_name": "u1", "extra_data": "e1"})
+        cache = {}
+        cached_conn = conn.execution_options(compiled_cache=cache)
+
+        upd = users.update().where(users.c.user_id == bindparam("b_user_id"))
+
+        with patch.object(
+            upd, "compile",
+                Mock(side_effect=upd.compile)) as compile_mock:
+            cached_conn.execute(
+                upd, util.OrderedDict([
+                    ("b_user_id", 1),
+                    ("user_name", "u2"),
+                    ("extra_data", "e2")
+                ])
+            )
+            cached_conn.execute(
+                upd, util.OrderedDict([
+                    ("b_user_id", 1),
+                    ("extra_data", "e3"),
+                    ("user_name", "u3"),
+                ])
+            )
+            cached_conn.execute(
+                upd, util.OrderedDict([
+                    ("extra_data", "e4"),
+                    ("user_name", "u4"),
+                    ("b_user_id", 1),
+                ])
+            )
+        eq_(compile_mock.call_count, 1)
+        eq_(len(cache), 1)
+
 
 class MockStrategyTest(fixtures.TestBase):