From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Wed, 19 Feb 2014 21:12:36 +0000 (-0500)
Subject: restore check ahead of the lock to avoid locking when not needed
X-Git-Tag: rel_0_8_5~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f9059f6cd8ccd9f50a9398f495fac89c85a83c29;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

restore check ahead of the lock to avoid locking when not needed
---

diff --git a/lib/sqlalchemy/event.py b/lib/sqlalchemy/event.py
index ec8481caf3..ab25c660f3 100644
--- a/lib/sqlalchemy/event.py
+++ b/lib/sqlalchemy/event.py
@@ -394,12 +394,13 @@ class _CompoundListener(object):
         """Execute this event, but only if it has not been
         executed already for this collection."""
 
-        with self._exec_once_mutex:
-            if not self._exec_once:
-                try:
-                    self(*args, **kw)
-                finally:
-                    self._exec_once = True
+        if not self._exec_once:
+            with self._exec_once_mutex:
+                if not self._exec_once:
+                    try:
+                        self(*args, **kw)
+                    finally:
+                        self._exec_once = True
 
 
     # I'm not entirely thrilled about the overhead here,