SQL Query Caching
Many sites use a database backend as a data store for the site. Whether the database contains product information, category structure, articles or a guest book, some of the data is likely to be quite static and will greatly benefit from a caching system.
Such a system would cache the results of an SQL query into a file stored on the system and hence improve the response time by avoiding the need to make a database connection, forming the query, executing it and retrieving the results.
On systems where the database does not reside on the same machine as the web server and requires a remote connection (TCP or similar), or where large amounts of data are retrieved from the database, you stand to gain even more in terms of response times and resources used.
