From 971e05c7d8d73f5178e8c2f7b8b3d7aa88575dc2 Mon Sep 17 00:00:00 2001
From: Ralph Bean <rbean@redhat.com>
Date: Jan 21 2015 05:14:00 +0000
Subject: Randomize preference order before calculating recipients


---

diff --git a/python-fmn-consumer-randomize.patch b/python-fmn-consumer-randomize.patch
new file mode 100644
index 0000000..1ccde59
--- /dev/null
+++ b/python-fmn-consumer-randomize.patch
@@ -0,0 +1,52 @@
+From 2aa92ed0dd8004df33b3c6de62b047caa895f96a Mon Sep 17 00:00:00 2001
+From: Ralph Bean <rbean@redhat.com>
+Date: Tue, 20 Jan 2015 09:49:25 -0500
+Subject: [PATCH] Randomize preference list per-thread.
+
+I'm noticing a weird behavior at FMN after restart.  All the threads lock on
+each other and do basically zero work as they wait for one of them to query
+pkgdb for individual users one after another.  Thread #1 queries pkgdb for
+ralph's packages and Threads 2-10 all wait for it to be done before moving on
+to the next preference to check.
+
+This should make each thread step through the preferences in a random order
+each time.  This means that while Thread #1 queries pkgdb for ralph's packages,
+Thread #2 will query pkgdb for pingou's packages, and Thread #3 will query
+pkgdb for till's packages, ..etc.  (Eventually all those package owning
+relationships get cached and we stop querying pkgdb).
+---
+ fmn/consumer/consumer.py | 11 ++++++++++-
+ 1 file changed, 10 insertions(+), 1 deletion(-)
+
+diff --git a/fmn/consumer/consumer.py b/fmn/consumer/consumer.py
+index 8a05489..21e8de4 100644
+--- a/fmn/consumer/consumer.py
++++ b/fmn/consumer/consumer.py
+@@ -1,6 +1,7 @@
+ # An example fedmsg koji consumer
+ 
+ import threading
++import random
+ 
+ import fedmsg.consumers
+ import fmn.lib
+@@ -164,7 +165,15 @@ class FMNConsumer(fedmsg.consumers.FedmsgConsumer):
+         # With cache management done, we can move on to the real work.
+         # Compute, based on our in-memory cache of preferences, who we think
+         # should receive this message.
+-        results = fmn.lib.recipients(self.cached_preferences, msg,
++
++        # First, make a thread-local copy of our shared cached prefs
++        preferences = list(self.cached_preferences)
++        # Shuffle it so that not all threads step through the list in the same
++        # order.  This should cut down on competition for the dogpile lock when
++        # getting pkgdb info at startup.
++        random.shuffle(preferences)
++        # And do the real work of comparing every rule against the message.
++        results = fmn.lib.recipients(preferences, msg,
+                                      self.valid_paths, self.hub.config)
+ 
+         # Let's look at the results of our matching operation and send stuff
+-- 
+2.1.0
+
diff --git a/python-fmn-consumer.spec b/python-fmn-consumer.spec
index 38fb142..2f12b46 100644
--- a/python-fmn-consumer.spec
+++ b/python-fmn-consumer.spec
@@ -8,7 +8,7 @@
 
 Name:               python-fmn-consumer
 Version:            0.4.4
-Release:            1%{?dist}
+Release:            2%{?dist}
 Summary:            Backend worker daemon for Fedora Notifications
 
 Group:              Development/Libraries
@@ -16,6 +16,8 @@ License:            LGPLv2+
 URL:                http://pypi.python.org/pypi/fmn.consumer
 Source0:            http://pypi.python.org/packages/source/f/%{modname}/%{modname}-%{version}.tar.gz
 
+Patch0:             python-fmn-consumer-randomize.patch
+
 BuildArch:          noarch
 
 BuildRequires:      python2-devel
@@ -43,6 +45,8 @@ This module contains the backend worker daemon for Fedora Notifications.
 %prep
 %setup -q -n %{modname}-%{version}
 
+%patch0 -p1
+
 # Remove bundled egg-info in case it exists
 rm -rf %{modname}.egg-info
 
@@ -61,6 +65,9 @@ rm -rf %{modname}.egg-info
 %{python2_sitelib}/%{modname}-%{version}*
 
 %changelog
+* Wed Jan 21 2015 Ralph Bean <rbean@redhat.com> - 0.4.4-2
+- Randomize preference order before calculating recipients.
+
 * Fri Jan 16 2015 Ralph Bean <rbean@redhat.com> - 0.4.4-1
 - new version