Magento Site Performance Optimization

Tuning, Scaling, and Replicating MySQL
We can easily bring proof of this stress imposed on MySQL by Magento to the
forefront. First, we have to delete the cache file of Magento, using the following
command, in order to be sure that all the data will be fetched from the database:
$ sudo rm –R /var/www/magento-optimization/var/cache/mage--*
Be sure to adapt the path to your installation. If the used path matches the different
installation steps discussed in the previous chapter, then we can activate the logging
mechanisms of MySQL. This mechanism is, by definition, performance killer as they
will write into a file every single operation our database engine does. Therefore,
be sure to deactivate it in a production environment. To do so, you have to edit the
main configuration file of MySQL with the following command:
$ sudo nano /etc/mysql/my.cnf
Look for #general_log_file in line 72 and uncomment it (remove the "#"). You can
now restart your MySQL server for the new configuration to be loaded by using the
following command:
$ sudo /etc/init.d/mysql restart
To be sure that we have sufficient data in our logging file, we first request the home
page of our Magento and then the usual furniture category. The generated logging
file is 352 lines long and is characterized by the following values:
• 179 selects
• 2 updates (log visitor)
• 4 inserts
• 0 delete
Some of the requests are very simple and we can assume that they do not cost too
much to be completed. However, some of them are composed of many jointure and
imbricated select. Here is an example of a fairly simple query and a much more
complex query:
select count(*) into @discard from 'information_schema'.'EVENTS';
In the preceding code, we have a simple count on the Events table. The following
one, however, has five inner jointures and many count and order operations:
SELECT 'attr_table'.* FROM 'catalog_category_entity_varchar' AS
'attr_table'
INNER JOIN 'eav_entity_attribute' AS 'set_table' ON
attr_table.attribute_id = set_table.attribute_id AND
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