Use time.perf_counter() for cache time measurement

See https://twitter.com/raymondh/status/1275937373080023040

Change-Id: Iaa0abb0c433ccedfbd88d00e3970120242ba379b

4 files changed, 5 insertions, 4 deletions

diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 1a8dbb4cd..cef719498 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -16,7 +16,6 @@ as the base class for their own corresponding classes.
 import codecs
 import random
 import re
-import time
 import weakref
 
 from . import cursor as _cursor
@@ -1027,7 +1026,7 @@ class DefaultExecutionContext(interfaces.ExecutionContext):
         if self.compiled is None:
             return "raw sql"
 
-        now = time.time()
+        now = util.perf_counter()
         if self.compiled.cache_key is None:
             return "no key %.5fs" % (now - self.compiled._gen_time,)
         elif self.cache_hit:
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 61178291a..b5e85ffb8 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -28,7 +28,6 @@ import contextlib
 import itertools
 import operator
 import re
-import time
 
 from . import base
 from . import coercions
@@ -482,7 +481,7 @@ class Compiled(object):
                 self.string = self.preparer._render_schema_translates(
                     self.string, schema_translate_map
                 )
-        self._gen_time = time.time()
+        self._gen_time = util.perf_counter()
 
     def _execute_on_connection(
         self, connection, multiparams, params, execution_options
diff --git a/lib/sqlalchemy/util/__init__.py b/lib/sqlalchemy/util/__init__.py
index 273570357..fb90975a1 100644
--- a/lib/sqlalchemy/util/__init__.py
+++ b/lib/sqlalchemy/util/__init__.py
@@ -61,6 +61,7 @@ from .compat import itertools_filterfalse  # noqa
 from .compat import namedtuple  # noqa
 from .compat import next  # noqa
 from .compat import parse_qsl  # noqa
+from .compat import perf_counter  # noqa
 from .compat import pickle  # noqa
 from .compat import print_  # noqa
 from .compat import py2k  # noqa
diff --git a/lib/sqlalchemy/util/compat.py b/lib/sqlalchemy/util/compat.py
index 5c46395f9..806ef8ae1 100644
--- a/lib/sqlalchemy/util/compat.py
+++ b/lib/sqlalchemy/util/compat.py
@@ -99,6 +99,7 @@ if py3k:
     from io import BytesIO as byte_buffer
     from io import StringIO
     from itertools import zip_longest
+    from time import perf_counter
     from urllib.parse import (
         quote_plus,
         unquote_plus,
@@ -192,6 +193,7 @@ else:
     from StringIO import StringIO  # noqa
     from cStringIO import StringIO as byte_buffer  # noqa
     from itertools import izip_longest as zip_longest  # noqa
+    from time import clock as perf_counter  # noqa
     from urllib import quote  # noqa
     from urllib import quote_plus  # noqa
     from urllib import unquote  # noqa