View source for Using caching to speed up your code

==Putting It All Together==
To compare speed we will now call the test method twice; once using the 'normal' way and once using caching. We'll wrap both calls in a profiler object so we can see the difference.
<source lang="php">
<?php

class TestClass {

    function testMethod() {

        // Get a reference to the global database object.
        $db = JFactory::getDBO();

        // Execute the same database query 250 times.
        for( $i=0; $i<250; $i++) {
            $db->setQuery( 'SELECT * FROM #__content' );
            $rows = $db->loadObjectList();
        }

        return $rows;
    }
}

// Get a reference to the global cache object.
$cache = JFactory::getCache();

// Run the test without caching.
$profiler = new JProfiler();
$rows = TestClass::testMethod();
echo $profiler->mark( ' without caching' );

// Run the test with caching.
$profiler = new JProfiler();
$rows  = $cache->call( array( 'TestClass', 'testMethod' ) );
echo $profiler->mark( ' with caching' );

?>
</source>
Now execute the component using ''index.php?option=com_testcache''. The first time you might see something like this:
 2.093 without caching
 2.160 with caching

The second one is a bit slower because the returned data needs to be written to a file. Now reload the page in your browser. 

 2.073 without caching
 0.008 with caching

Multiply those numbers by the number of hits your site gets in 900 seconds (the default time Joomla! stores the cached data). Not bad huh? Again, reload the page a couple of times and you will see small differences in the numbers.