Understanding mysqltuner Recomendations w/ Unused Catalogs

Question

I have a MySQL 5.0.77 instance running with three catalogs in it.

Two of the catalogs contain all InnoDB tables and are actively used.

The third is all MyISAM and is basically unused, and is only still in the server as a precaution. Basically, it is an old version of one of the other catalogs that used to be referenced to ensure that data migration was correct.

I have been running mysqltuner periodically so I can get a decent baseline configuration before I begin real profiling on whole system.

Even though I am not querying or even opening connections to the MyISAM catalog, is its presence throwing off the mysqltuner recommendations?

For example, can I truly ignore the warnings about key_buffer_size, or will bad values for this negatively impact the whole server even when I am not really using MyISAM?

Is having this unused catalog negatively impacting the memory footprint of the server? If so, is there any way to mitigate this, other than moving the catalog somewhere else and doing a DROP?

Thanks.

Answer 1

If you know that the MyISAM tables are not being actively queried, not only can you ignore recommendations for key_buffer_size, you could actually lower it.

What can you do with the extra RAM you just reclaimed? One or more of the following options:

• OPTION 1) Add that number to innodb_buffer_pool_size
• OPTION 2) Slightly increase max_connections
• OPTION 3) Slightly increase by 1M (given to each DB Connection) one or more of the following
  • join_buffer_size
  • sort_buffer_size
  • read_buffer_size
  • read_rnd buffer_size

After restarting mysqld, rerun mysqltuner and evaluate the resulting recommendations. Taking key_buffer_size out of the equation is enough in your instance.