mysql 5 vs 5.5 memory usage

Question

I had a less less memory usage in mysql 5 vs 5.5 do they do something drastically different? I went from around 100mb to about 1 gb of memory usage.

Does memory usage in 5.5 also grow over time?

Answer 1

I don't know exactly if 5.5 require much memory than 5.0 but look this example :

In 5.0 MySQL Official Documentation:

innodb_buffer_pool_size : The default value is 8MB.

In 5.5 MySQL Official Documentation:

innodb_buffer_pool_size : The default value is 128MB.

If you paste your both "show global variables" results (5.0 and 5.5) we'll can see exactly what variables have gone up...

Max.

Answer 2

Tuning advice: http://mysql.rjweb.org/doc.php/memory . Note that the main thing is to set the innodb_buffer_pool_size appropriately if you are using InnoDB. The old 8MB was terribly small, but not an issue when few people were using InnoDB. The new default of 128MB is too small for today's machines (unless your data is that small).

If you are using MyISAM, the key_buffer creeps up, but stops at key_buffer_size. (That's the biggest creeper I know of.)

As you get more simultaneous users, the "stack" for each adds up. See thread_cache_size.

Etc.

Properly tuned, a server will reach some max, then fluctuate slightly. Uptime (SHOW STATUS LIKE 'Uptime';) of more than a year is not a problem. (I see one machine that has been up for 131,379,337 seconds. It's running version 4.1.22; long overdue for an upgrade.)