MySQL, Linux, Web

Redis, Memcached, Tokyo Tyrant and MySQL comparision

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I wanted to compare the following DBs, NoSQLs and caching solutions for speed and connections. Tested the following

My test had the following criteria

  • 2 client boxes
  • All clients connecting to the server using Python
  • Used Python’s threads to create concurrency
  • Each thread made 10,000 open-close connections to the server
  • The server was
    • Intel(R) Pentium(R) D CPU 3.00GHz
    • Fedora 10 32bit
    • Intel(R) Pentium(R) D CPU 3.00GHz
    • 2.6.27.38-170.2.113.fc10.i686 #1 SMP
    • 1GB RAM
  • Used a md5 as key and a value that was saved
  • Created an index on the key column of the table
  • Each server had SET and GET requests as a different test at same concurrency

Results please !

Work sheet

throughput set

throughput get

I wanted to simulate a situation where I had 2 servers (clients) serving my code, which connected to the 1 server (memcached, redis, or whatever). Another thing to note was that I used Python as the client in all the tests, definately the tests would give a different output had I used PHP. Again the test was done to check how well the clients could make and break the connections to the server, and I wanted the overall throughput after making and breaking the connections. I did not monitor the response times. I didnt change absolutely any parameters for the servers, eg didn’t change the innodb_buffer_pool_size or key_buffer_size.

MySQL

MySQL lacked the whole scene terribly, I monitored the MySQL server via the MySQL Administrator and found that hardly there were any conncurrent inserts or selects, I could see the unauthenticated users, which meant that the client had connected to MySQL and was doing a handshake using MySQL authentication (using username and password). As you could see I didn’t even perform the 40 and 60 thread tests.

I truncated the table before I swtiched my tests from MyISAM to InnoDB. And always started the tests from lesser threads. My table was as follows

CREATE TABLE `comp_dump` (
  `k` char(32) DEFAULT NULL,
  `v` char(32) DEFAULT NULL,
  KEY `ix_k` (`k`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1

NoSQL

For Tokyo Tyrant I used a file.tch as the DB, which is a hash database. I also tried MongoDB as u may find if u have opened the worksheet, But the server kept failing or actually the mongod failed after coming at an unhandled Exception. I found something similar over here. I tried 1.0.1, 1.1.3 and the available Nightly build, but all failed and I lost my patience.

Now what

If you need speed just to fetch a data for a given combination or key, Redis is a solution that you need to look at. MySQL can no way compare to Redis and Memcache. If you find Memcache good enough, you may want to look at Tokyo Tyrant as it does a synchronous writes. But you need to check for your application which server/combination suits you the best. In Marathi there is a saying “मेल्या शिवाय स्वर्ग दिसत नाही”, which means “You can’t see heaven without dieing” or need to do your hard work, can’t escape that 😉

I’ve attached the source code used to test, if anybody has any doubts, questions feel free to ask

Web

How sessions work in PHP

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HTTP is a stateless protocol. Which means that every request the browser makes to the server cant be identified by the server as a subsequent request of that user/IP/browser or a brand new request.

HTTP doesn’t understand who is requesting. So how do sessions manage to make HTTP look intelligent? The Answer lies in the request-response model with data.


When a normal request is made, eg my website, the minimalistic data passed by the client/browser is this

GET / HTTP/1.1
Host: ruturaj.net

The server responds by giving the output. But when a developer does a session_start();, What actually happens is, the PHP engine sets a PHPSESSID cookie. This data is sent from the Server as Set-Cookie header. So the response goes somewhat like this

HTTP/1.x 200 OK
Date: xxxx
Set-Cookie: PHPSESSID=<32charhexvalue>; expires=xxxx
...

Now considering the browser does accept the cookies, it saves the PHPSESSID cookie. Consequently the server also creates a file in the specified directory (by default on Linux as /tmp) as /tmp/sess_32charid.

Now when another request is made by the user/browser, the Cookie header is passed through the GET request back to the server, something like this…

GET /session2.php HTTP/1.1
Host: ruturaj.net
Cookie: PHPSESSID=<32charid>; othercookies=othervalues;

The session2.php, for example, is setting a value of name in session, by this

$_SESSION['name'] = $name_obtained_from_somewhere;

Now as the script finishes, the script flushes all the $_SESSION data into the /tmp/sess_32charid file associated to that session id. It saves all the data in the serialized format

Consider the browser makes another request to session3.php where $_SESSION['name'] is echoed. Now when the request is made, just like previous case, the PHPSESSID is passed in the cookie.

Now as mandated by php.net, that every page where sessions should be needed, a session_start(); is required. So as soon this function is invoked, PHP checks if the browser’s request had any PHPSESSID cookie sent in the header, as it was sent in our case, PHP Engine will open /tmp/sess_32charid file (with the same session id) and unserialize the contents of the file. It then assigns the values of the unserialized data structures to the $_SESSION variable.

The simple echo $_SESSION['name']; will now be able to output the name!! Sessions working…

On a session_destroy();, PHP sends a destructive, previous timestamp cookie for PHPSESSID and unlinks or deletes the /tmp/sess_32charid file. This ensures that no reference of that session is left.

References

  • http://in3.php.net/manual/en/session.configuration.php
Uncategorized

Automated MP3 tags updation with python

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Had a wonderful song collection of Old hindi songs, in the format of “somenumber title (moviename).mp3”. Had to find way to update the ID3 tag info. Opensource to help yet again.

Installed a module named python-id3, Using yum install python-id3. Then wrote a small script in python using regular expressions, glob and the newly installed MP3 ID3 tagging module

#!/bin/env python

import os, glob, re, sys
from ID3 import *

def strip(str):
	return str.lstrip().rstrip()

os.chdir('/media/Carrington/Music/old-hindi-hit')
mp3s = glob.glob('*.mp3')

r = re.compile('([\d]+(([\s])*?[\w\s]+)\s?(\((.*?)\)?)?)\.mp3', re.I)

i = 1
for mp3 in mp3s:
	print str(i) + ": " + mp3
	gr = r.match(mp3)
	#print gr.groups()

	id3info = ID3(open(mp3, 'r+b'), mp3)
	title = ''
	album = ''
	try:
		if (len(gr.groups()) >= 4):
			print "Title: %s, Album: %s" % (strip(gr.group(2)), strip(gr.group(5)))
			title = strip(gr.group(2))
			album = strip(gr.group(5))
		else:
			print "Title: %s" % (strip(gr.group(2)))
			title = strip(gr.group(2))
		
		id3info.title = title
		id3info.album = album
		id3info.genre = 'Old Hindi'
		id3info.artist = ''
		id3info.write()
	except:
		print sys.exc_info()
	
	i = i + 1

Uncategorized

Gmail style Static message box using jQuery

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If u want to see a gmail style, “Loading” message box on ur application, its extremely simple using jQuery and CSS. All u need to know is

  1. jQuery
  2. HTML and good CSS, duh!

A ‘fixed’ element

First u need to have a fixed element, so u can define a div and give it css property as position: fixed;

jQuery methods to show, hide messages

U need to take a reference of the element, and then apply jQuery’s fadeIn and fadeOut method. A simple setTimeout can be set to automatically hide the message.

function notify(message, timeOut) {
	// Set the message using text method and chain fadeIn with it
	// apply simple setTimeout to fadeOut the message
	$('#boxd').text(message).fadeIn();
	setTimeout(function(){
		$('#boxd').fadeOut();
	}, timeOut*1000);
}

$(function(){
	// Wait to attach a event handler for the demo button
	$('#btn').click(function(){
		notify(new Date().toString(), 5);
	});
});

Check the attached example.

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hands itching…

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my hands are itching to write something, I don’t know what.. hmm.. Let me think. trek-a-log (i’ve been to none since long), life (I don’t really think much about it, sometimes)… perhaps something technical then..

Perhaps somebody reading this blog can suggest me, mail me @ ruturaj at gmail dot com

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Kim Clijsters 2009 US Open Champion

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Kim Clijsters was back with her best, becoming the first wild-carded entry winning the US Open against Caroline Wozniacki. It was a dream run for the young Dane, Caroline. Finally Kim’s experience was just too much. It ended 7-5, 6-3

Wozniacki Serves
Wozniacki Serves

Kim-backhand
Kim-backhand

Wozniacki misses
Wozniacki misses

Strong Clijsters
Strong Clijsters

Wozniacki gets some points
Wozniacki gets some points

Jada with her US Open champion mommy
Jada with her US Open champion mommy

Wozniacki still cheerful as a runner up
Wozniacki still cheerful as a runner up

Wozniacki still cheerful as a runner up
Wozniacki still cheerful as a runner up

Great comeback for Clijsters
Great comeback for Clijsters

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