From 97294ef2fd5737a58ff0a5d551a17e77dcf1baaf Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 9 Feb 2016 10:10:20 +0000
Subject: [PATCH] Create new context when measuring

---
 synapse/util/metrics.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/synapse/util/metrics.py b/synapse/util/metrics.py
index ca48007218..f70d855122 100644
--- a/synapse/util/metrics.py
+++ b/synapse/util/metrics.py
@@ -48,26 +48,29 @@ block_db_txn_duration = metrics.register_distribution(
 
 
 class Measure(object):
-    __slots__ = ["clock", "name", "start_context", "start"]
+    __slots__ = ["clock", "name", "start_context", "start", "new_context"]
 
     def __init__(self, clock, name):
         self.clock = clock
         self.name = name
         self.start_context = None
         self.start = None
+        self.new_context = LoggingContext(self.name)
 
     def __enter__(self):
         self.start = self.clock.time_msec()
         self.start_context = LoggingContext.current_context()
+        self.new_context.__enter__()
 
     def __exit__(self, exc_type, exc_val, exc_tb):
+        self.new_context.__exit__(exc_type, exc_val, exc_tb)
         if exc_type is not None:
             return
 
         duration = self.clock.time_msec() - self.start
         block_timer.inc_by(duration, self.name)
 
-        context = LoggingContext.current_context()
+        context = self.new_context
 
         if context != self.start_context:
             logger.warn(