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

• Redis
• Memcached
• Tokyo Tyrant / Tokyo Cabinet
• MySQL 5.1.40 (MyISAM)
• MySQL 5.1.40 (with Innodb Plugin 1.0.4), compiled into source of MySQL

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 !

I found out the hashing algorithm used in PHP-Memcache is different from that of Python-Memcache. The keys went to different servers as the hash created by python and php were different.

I posted a question on the memcache groups and was lucky to find this wonderful reply.

import memcache
import binascii
m = memcache.Client(['192.168.28.7:11211', '192.168.28.8:11211
', '192.168.28.9:11211'])

def php_hash(key):
    return (binascii.crc32(key) >> 16) & 0x7fff

for i in range(30):
       key = 'key' + str(i)
       a = m.get((php_hash(key), key))
       print i, a

This is the only thing that has to be done on Python's end, change the way the hash is calculated. The coding on PHP end remains same. All you guys using PHP for web based front-end with MySQL and Python for back-end scripts shall find this helpful.

Thanks Brian Rue.

Reference: http://groups.google.com/group/memcached/msg/7bb75a026c44ec43