Changes are made at your own risk and are not guaranteed to work. Always make backups of the database and files prior to implementing hacks. Make a special backup of the file and/or template you are modifying so that you can roll back quickly.
Hacks are dangerous and can cause your site to stop working. They make later updates to ExpressionEngine more difficult; you should track your hacks for post-update re-implementation.
Most hacks are unnecessary, please review the Development Documentation for information on expanding ExpressionEngine via Modules, Extensions, and Plugins.
Hacks are never officially supported.
Question:
How can I get EE to keep search terms around longer?
Answer:
Go to /system/modules/search/mod.search.php and find
var $cache_expire = 24; // How many hours should we keep search caches?
Modify 24 to whatever number of hours you want.
Further, the table exp_search stores all this:
* search_id
* search_date
* keywords
* member_id
*ip_address
* total_results
* per_page
* query
So a query could be built to pull out that information.