MySQL 5.1 or 5.5?

Solution 1:

These days, you can use MySQL 5.5 now. I have 5.5.9 in production right now and it's running great.

I have successfully scaled MySQL 5.5 with simple circular replication amonst 3 DB Servers. Here is the layout of each DB server and what's running

  • MySQL 5.5.9
  • 2TB RAID10 SAS
  • 192GB RAM
  • One monolithic 162GB InnoDB Buffer Pool
  • Dual HexaCore (that's right, 12 CPUs)

/etc/my.cnf has the following

[mysqld]
innodb_read_io_threads=64
innodb_write_io_threads=64
innodb_io_capacity=65536
innodb_buffer_pool_instances=1
innodb_bufer_pool_size=162G

Each MySQL Server contains

  • 942 client (tenant) databases
  • 935GB total data
  • 95% of the buffer pool is full on all three servers

After 1 year, it still runs like a dream because of using MySQL 5.5 and getting InnoDB to engage all 12 CPUs.

So, I am quite happy with its performance thus far and so it the client.

Solution 2:

5.5 is a development release and not suitable for production. Unless you have a specific reason to, you should not even consider running 5.5 for any production use.

Solution 3:

Neither. Use percona 5.1 with xtra-db. Percona.com It's as fast as 5.5, and does lots of things MySQL should be doing. It's free, based on, and is binary compatible as a drop in replacement for MySQL. I've yet to have anything but good experiences running percona instead of MySQL. Make sure you set the default engine to innodb. Show engines; will show you are using xtradb instead of innodb.

Solution 4:

You should actually use mysql 5.0, the query planner does a better job with vbulletin than 5.5. We found several areas where 5.5's query planner resulted in worse performance overall than 5.0 and thus switched back.

http://www.makingitscale.com/2010/latest-mysql-query-planner-gone-looney.html