46 lines
2.0 KiB
PHP
46 lines
2.0 KiB
PHP
<?php ?>
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Doctrine_Cache offers an intuitive and easy-to-use query caching solution. It provides the following things:
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<ul>
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<li \> Multiple cache backends to choose from (including Memcached, APC and Sqlite)
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<br \><br \>
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<li \> Manual tuning and/or self-optimization. Doctrine_Cache knows how to optimize itself, yet it leaves user
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full freedom of whether or not he/she wants to take advantage of this feature.
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<br \><br \>
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<li \> Advanced options for fine-tuning. Doctrine_Cache has many options for fine-tuning performance.
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<br \><br \>
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<li \> Cache hooks itself directly into Doctrine_Db eventlistener system allowing it to be easily added on-demand.
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</ul>
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<br \><br \>
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Doctrine_Cache hooks into Doctrine_Db eventlistener system allowing pluggable caching.
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It evaluates queries and puts SELECT statements in cache. The caching is based on propabalistics. For example
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if savePropability = 0.1 there is a 10% chance that a query gets cached.
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<br \><br \>
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Now eventually the cache would grow very big, hence Doctrine uses propabalistic cache cleaning.
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When calling Doctrine_Cache::clean() with cleanPropability = 0.25 there is a 25% chance of the clean operation being invoked.
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What the cleaning does is that it first reads all the queries in the stats file and sorts them by the number of times occurred.
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Then if the size is set to 100 it means the cleaning operation will leave 100 most issued queries in cache and delete all other cache entries.
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<br \><br \>
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<br \><br \>
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Initializing a new cache instance:
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<br \><br \>
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<?php
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renderCode("<?php
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\$dbh = new Doctrine_Db('mysql:host=localhost;dbname=test', \$user, \$pass);
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\$cache = new Doctrine_Cache('memcache');
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// register it as a Doctrine_Db listener
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\$dbh->addListener(\$cache);
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?>");
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?>
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<br \><br \>
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Now you know how to set up the query cache. In the next chapter you'll learn how to tweak the cache in order to get maximum performance.
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<br \><br \>
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