Apachebench request count and Node.js script counter don't match - node.js

Question

No doubt I'm doing something stupid, but I've been having problems running a simple node.js app using the Nerve micro-framework. Testing with apachebench, it seems that the code within my single controller is being invoked more frequently than the app itself is being called.
I've created a test script like so:
'use strict';
(function () {
var path = require('path');
var sys = require('sys');
var nerve = require('/var/www/libraries/nerve/nerve');
var nerveCounter = 0;
r_server.on("error", function (err) {
console.log("Error " + err);
});
var app = [
["/", function(req, res) {
console.log("nc = " + ++nerveCounter);
}]
];
nerve.create(app).listen(80);
}());
Start the server. From another box, run a load test:
/usr/sbin/ab -n 5000 -c 50 http://<snip>.com/
...
Complete requests: 5000
...
Percentage of the requests served within a certain time (ms)
...
100% 268 (longest request)
But the node script itself is printing all the way up to:
nc = 5003
rc = 5003
In other words, the server is being called 5000 times but the controller code is being called 5003 times.
Any ideas what I'm doing wrong?
Updated
I changed the tone and content of this question significantly to reflect the help Colum, Alfred and GregInYEG gave me in realising that the problem did not lie with Redis or Nerve and probably lie with apachebench.

Answer 1

Program:
const PORT = 3000;
const HOST = 'localhost';
const express = require('express');
const app = module.exports = express.createServer();
const redis = require('redis');
const client = redis.createClient();
app.get('/incr', function(req, res) {
client.incr('counter', function(err, reply) {
res.send('incremented counter to:' + reply.toString() + '\n');
});
});
app.get('/reset', function(req, res) {
client.del('counter', function(err, reply) {
res.send('resetted counter\n');
});
});
app.get('/count', function(req, res) {
client.get('counter', function(err, reply) {
res.send('counter: ' + reply.toString() + '\n');
});
});
if (!module.parent) {
app.listen(PORT, HOST);
console.log("Express server listening on port %d", app.address().port);
}
Conclusion
It works without any flaws on my computer:
$ cat /etc/issue
Ubuntu 10.10 \n \l
$ uname -a
Linux alfred-laptop 2.6.35-24-generic #42-Ubuntu SMP Thu Dec 2 01:41:57 UTC 2010 i686 GNU/Linux
$ node -v
v0.2.6
$ npm install express hiredis redis
npm info build Success: redis#0.5.2
npm info build Success: express#1.0.3
npm info build Success: hiredis#0.1.6
$ ./redis-server --version
Redis server version 2.1.11 (00000000:0)
$ git clone -q git#gist.github.com:02a3f7e79220ea69c9e1.git gist-02a3f7e7; cd gist-02a3f7e7; node index.js
$ #from another tab
$ clear; curl http://localhost:3000/reset; ab -n 5000 -c 50 -q http://127.0.0.1:3000/incr > /dev/null; curl http://localhost:3000/count;
resetted counter
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking 127.0.0.1 (be patient)
Completed 500 requests
Completed 1000 requests
Completed 1500 requests
Completed 2000 requests
Completed 2500 requests
Completed 3000 requests
Completed 3500 requests
Completed 4000 requests
Completed 4500 requests
Completed 5000 requests
Finished 5000 requests
Server Software:
Server Hostname: 127.0.0.1
Server Port: 3000
Document Path: /incr
Document Length: 25 bytes
Concurrency Level: 50
Time taken for tests: 1.172 seconds
Complete requests: 5000
Failed requests: 4991
(Connect: 0, Receive: 0, Length: 4991, Exceptions: 0)
Write errors: 0
Total transferred: 743893 bytes
HTML transferred: 138893 bytes
Requests per second: 4264.61 [#/sec] (mean)
Time per request: 11.724 [ms] (mean)
Time per request: 0.234 [ms] (mean, across all concurrent requests)
Transfer rate: 619.61 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.5 0 7
Processing: 4 11 3.3 11 30
Waiting: 4 11 3.3 11 30
Total: 5 12 3.2 11 30
Percentage of the requests served within a certain time (ms)
50% 11
66% 13
75% 14
80% 14
90% 15
95% 17
98% 19
99% 24
100% 30 (longest request)
counter: 5000