implement cython for cache_anon_map, prefix_anon_map

These are small bits where cache_anon_map in particular
is part of the cache key generation scheme which is a key
target for cython.

changing such a tiny element of the cache key gen is
doing basically nothing yet, as the cython impl is
mostly the exact same speed as the python one.  I guess for
cython to be effective we'd need to redo the whole cache key
generation and possibly not use the same kinds of structures,
which might not be very easy to do.

Additionally, some cython runtime import errors are being
observed on jenkins, add an upfront check to the test suite
to indicate if the expected build succeeded when REQUIRE_SQLALCHEMY_CEXT
is set.

Running case CacheAnonMap
Running python .... Done
Running cython .... Done
                    | python      | cython      | cy / py     |
test_get_anon_non_present| 0.301266758 | 0.231203834 | 0.767438915 |
test_get_anon_present| 0.300919362 | 0.227336695 | 0.755473803 |
test_has_key_non_present| 0.152725077 | 0.133191719 | 0.872101171 |
test_has_key_present| 0.152689778 | 0.133673095 | 0.875455428 |
Running case PrefixAnonMap
Running python .. Done
Running cython .. Done
                    | python      | cython      | cy / py     |
test_apply_non_present| 0.358715744 | 0.335245703 | 0.934572034 |
test_apply_present  | 0.354434996 | 0.338579782 | 0.955266229 |

Change-Id: I0d3f1dd285c044afc234479141d831b2ee0455be

1 files changed, 15 insertions, 0 deletions

diff --git a/lib/sqlalchemy/testing/plugin/plugin_base.py b/lib/sqlalchemy/testing/plugin/plugin_base.py
index 7bc88a14b..2a6691fc8 100644
--- a/lib/sqlalchemy/testing/plugin/plugin_base.py
+++ b/lib/sqlalchemy/testing/plugin/plugin_base.py
@@ -16,6 +16,7 @@ is pytest.
 import abc
 import configparser
 import logging
+import os
 import re
 import sys
 
@@ -370,6 +371,20 @@ def _monkeypatch_cdecimal(options, file_config):
 
 
 @post
+def __ensure_cext(opt, file_config):
+    if os.environ.get("REQUIRE_SQLALCHEMY_CEXT", "0") == "1":
+        from sqlalchemy.util import has_compiled_ext
+
+        try:
+            has_compiled_ext(raise_=True)
+        except ImportError as err:
+            raise AssertionError(
+                "REQUIRE_SQLALCHEMY_CEXT is set but can't import the "
+                "cython extensions"
+            ) from err
+
+
+@post
 def _init_symbols(options, file_config):
     from sqlalchemy.testing import config