Caching

A Doctrine\DBAL\Statement can automatically cache result sets. The feature is optional though, and by default, no result set is cached.

To use the result cache, there are three mandatory steps:

  1. Configure a global result cache, or provide one at query time.
  2. Provide a cache profile for the result set you want to cache when making a query.
  3. Read the entire result set from the database.

Configuring the result cache

Any instance of Doctrine\Common\Cache\Cache can be used as a result cache and can be set on the configuration object (optionally it can also be passed at query time):

1<?php $cache = new \Doctrine\Common\Cache\ArrayCache(); $config = $conn->getConfiguration(); $config->setResultCacheImpl($cache);
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Providing a cache profile

To get the result set of a query cached, it is necessary to pass a Doctrine\DBAL\Cache\QueryCacheProfile instance to the executeQuery() or executeCacheQuery() methods. The difference between these two methods is that the former has the cache profile as an optional argument, whereas it is required when calling the latter:

1<?php $stmt = $conn->executeQuery($query, $params, $types, new QueryCacheProfile(0, "some key")); $stmt = $conn->executeCacheQuery($query, $params, $types, new QueryCacheProfile(0, "some key"));
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As stated before, it is also possible to pass in a Doctrine\Common\Cache\Cache instance into the constructor of Doctrine\DBAL\Cache\QueryCacheProfile in which case it overrides the default cache instance:

1<?php $cache = new \Doctrine\Common\Cache\FilesystemCache(__DIR__); new QueryCacheProfile(0, "some key", $cache);
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Reading the entire result set

Caching half a result set would cause bugs if a subsequent caller needed more rows from that same result sets. To be able to cache the entire result set, it must be fetched entirely from the database, and not all APIs do that. The easiest way to ensure that is to use one of the fetchAll*() methods:

1<?php $stmt = $conn->executeCacheQuery($query, $params, $types, new QueryCacheProfile(0, "some key")); $data = $stmt->fetchAllAssociative();
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When using the cache layer not all fetch modes are supported. See the code of the Doctrine\DBAL\Cache\ResultCacheStatement for details.