Cache Zend_Db_Table MetaData with Zend_Cache

In this afternoon, my boss asked me to improve performance of project to release to client before Lunar new year holidays. The problem is: we have too many DESCRIBE query on every page load. I Google-ed & found the Lysender‘s solution, simple & easy to fix this problem:

When you are using Zend_Db_Table (I sometimes only used Zend_Db) you will notice that when you try to retrieve data from the database, the first query called is to DESCRIBE the table. Zend_Db_Table uses the information on DESCRIBE query to do its magic on SELECT.

As I have profiled my queries, I noticed that DESCRIBE query is the longest query (in most cases) which mean a big overhead over you retrieval operation. You have two options:

1. Don’t use Zend_Db_Table (go for Zend_Db)
2. Cache the MetaData

On this post, I’ll use the caching of MetaData. On your bootstrap file, put this piece of code:

	//Caching
	$frontendOptions = array(
					'lifetime'				 => 25200,
	    				'automatic_serialization' => true
	    				);
	$backendOptions  = array(
	   					 'cache_dir'  => APPLICATION_PATH . '/tmp'
	    				);
	$cache = Zend_Cache::factory(
				'Core',
	                        'File',
	                        $frontendOptions,
	                        $backendOptions
	                    );
	//Cache table metadata
	Zend_Db_Table_Abstract::setDefaultMetadataCache($cache);

The code simply instructs Zend_Db_Table_Abstract to cache the result of DESCRIBE statement so that next time you retrieve data, the cache is used instead of repeatedly describing tables over and over again.

(But I noticed that INSERT and UPDATE statements don’t have DESCRIBE…)

After several tries with this caching, you will see files on the tmp folder like this: zend_cache—internal-metadatas—5e7576e3cd79114d46850714e998a3b0.

Still there is an overhead on reading the cache file. If you want better caching, use memory based caching like MemCache.

Source: http://lysender.co.cc/2009/03/zend-framework-optimization-tips