MySQL performance impact of increasing innodb_buffer_pool_size
If you want to size the innodb_buffer_pool_size bigger please run this:

SELECT CEILING(SUM(data_length+index_length)/POWER(1024,2)) RIBPS
FROM information_schema.tables WHERE engine='InnoDB';


This will give you the maximum amount of InnoDB Buffer Pool needed for your current data set.

Given the amount of data and index pages for your dataset, having 8MB Buffer Pool will just cause data and index pages accessed to rotate out and load new pages as needed. Setting it with the value based on that RIBPS query (RIBPS stands for Recommended InnoDB Buffer Pool Size), all of InnoDB will be accessed from RAM. Having the Buffer Pool too big would just wastes RAM.

Let's say that you ran this query and got the following:

mysql&gt; SELECT CEILING(SUM(data_length+index_length)/POWER(1024,2)) RIBPS
    -&gt; FROM information_schema.tables WHERE engine='InnoDB';
+-------+
| RIBPS |
+-------+
|  1493 |
+-------+


Take that number and place it in /etc/my.cnf

[mysqld]
innodb_buffer_pool_size=1493M


and restart mysql.

I have discussed this before


Apr 14, 2011 : What are the main differences between InnoDB and MyISAM?
Jan 11, 2012 : MySQL said &quot;InnoDB: Initializing buffer pool, size = 128.0M&quot;, does it mean it is using 128MB RAM?
Jun 13, 2012 : What to set innodb_buffer_pool and why..?
Oct 22, 2012 : How large should be mysql innodb_buffer_pool_size?


Give it a Try !!!