DiY-CMS
New DiY-CMs features 1: reducing queries by 50-85%
By:
admin 
Date Added:
Wednesday 09-02-2011
After I finished programming my first app for facebook - Friends Stat, I started thinking about new ways to improve DiY-CMS. I have many ideas to develop but there are three features of them which I believe are important. They are: cache system to minimise mysql queries, adding php code into main templates and improving the update system in DiY-CMS control panel.
I will explain the first feature in this blog and then talk about the rest in later blogs.
Cache system is developed to ease the process of retrieving data from database. In other words cache system saves the results of repetitive queries that do not change often into files and then retrieve the data from these files rather that querying database again and again. As you might have guessed by now, this process will reduce the load on database and increase the cms performance.
In DiY-CMS there are number of queries that do not change often such as general settings, module settings, plugins details, themes, templates and other queries. Cache system will save the results of each one of these queries to a single file and place it in cache folder. Once a query is requested in the front-end DiY-CMS will check if there is a cache file relevant to that query and retrieve results saved in it, otherwise the query will run normally.
Cache files do not have expiry data, so files would remain for unlimited period of time. What if I make changes to settings, theme or templates? In this case the relevant cache file would be updated automatically once changes occur in the control panel. Also, you can remove cache files manually from Cache folder any time you whish and DiY-CMS will create new cache files.
This feature reduces mysql queries and therefore increases overall performance. In some pages of DiY-CMS queries reached as little as 1 query per page. Certainly the number of queries cached would be different from module to another and one page to other pages but on average mysql queries have been minimised by 50-85%. See chart below.
Furthermore, you can use this system to cache queries that you might use in modules, plugins or blocks you develop for DiY-CMS. Implementing cache is easy and requires three functions one to create the cache file, second one to check file existence.
Say we have this query that we want to cache:
$result = $diy_db->query("SELECT variable,value FROM diy_settings");
You would be place this code in the place where the data of diy_settings is updated:
// Query database table
while ($row = $diy_db->dbarray($query_result)) {
$key = $row['variable'];
$array[$key] = $row['value'];
}
// create a cache file and save data into it
$diy_db->create_query_cache_file('global_settings', $array);
Notice that create_query_cache_file() function takes two parameters, the first one is the file name and the second one is query data that needs to be cached.
Then you would use this code to check for the file and retrieve its data:
// check if file exists
$cahce = $diy_db->check_query_cache_file('global_settings');
if ($cahce) {
// if file exists retrieve its data and place them in a varaible
$array = $diy_db->get_query_cache_file('global_settings');
} else {
// if file does not exist proceed with query as normal
$result = $diy_db->query("SELECT variable,value FROM diy_settings");
while ($row = $diy_db->dbarray($result, $i++)) {
$key = $row['variable'];
$array[$key] = $row['value'];
}
}
// here $array data can be used as whished
In the last code snippet there are two important functions, the first one is check_query_cache_file() which checked if file exists and the second retrieve data from the cache file. Both functions take one parameter and it is the file name that we creates using create_query_cache_file() fcuntion.
I hope that this blog provides some insights into the feature of DiY-CMS and how to use them.
In next blog I will explain the rest of features.
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