From 50ccce80142713b45555608ab8da0600a500b1d9 Mon Sep 17 00:00:00 2001
From: Vadim Semenov <v.semenov@ivideon.com>
Date: Mon, 27 Mar 2017 12:30:07 +0300
Subject: [PATCH] Use TCP_NODELAY for improved latency

According to the NSQ protocol, consumers have to send `FIN`s for every
message they receive, which makes them extremely slow with low `max_in_flight`
values due to TCP buffering.

Adding TCP_NODELAY option on `async.AsyncConn`'s sockets makes `nsq.Reader`
substantially faster. My tests show increase from ~50 to ~4.5K messages per
second on localhost.
---
 .gitignore   | 4 ++++
 nsq/async.py | 1 +
 2 files changed, 5 insertions(+)

diff --git a/.gitignore b/.gitignore
index 44d229a..47ae6e7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,7 @@ dist
 pynsq.egg-info
 build
 docs/_build
+.cache
+.eggs
+*.dat
+*.tmp
diff --git a/nsq/async.py b/nsq/async.py
index c3a71cb..c4fddb7 100644
--- a/nsq/async.py
+++ b/nsq/async.py
@@ -225,6 +225,7 @@ def connect(self):
 
         self.stream = tornado.iostream.IOStream(self.socket, io_loop=self.io_loop)
         self.stream.set_close_callback(self._socket_close)
+        self.stream.set_nodelay(True)
 
         self.state = CONNECTING
         self.on(event.CONNECT, self._on_connect)