It is highly recommended to make use of a bytecode cache like OPcache. A bytecode cache removes the need for parsing PHP code on every request and can greatly improve performance.
If you care about performance and don't use a bytecode cache then you don't really care about performance. Please get one and start using it.
Stas Malyshev, Core Contributor to PHP and Zend Employee
As already mentioned earlier in the chapter about configuring Doctrine, it is strongly discouraged to use Doctrine without a Metadata and Query cache.
Operating Doctrine without these caches means Doctrine will need to load your mapping information on every single request and has to parse each DQL query on every single request. This is a waste of resources.
The preferred cache adapter for metadata and query caches is a PHP file cache like Symfony's PHP files adapter. This kind of cache serializes cache items and writes them to a file. This allows for opcode caching to be used and provides high performance in most scenarios.
Make effective use of the available alternative query result formats like nested array graphs or pure scalar results, especially in scenarios where data is loaded for read-only purposes.
You can mark entities as read only. For details, see Attributes Reference
This means that the entity marked as read only is never considered for updates. During flush on the EntityManager these entities are skipped even if properties changed.
Read-Only allows to persist new entities of a kind and remove existing ones, they are just not considered for updates.
You can also explicitly mark individual entities read only directly on the
UnitOfWork via a call to
Or you can set all objects that are the result of a query hydration to be marked as read only with the following query hint:
If entities hold references to large collections you will get performance and memory problems initializing them. To solve this issue you can use the EXTRA_LAZY fetch-mode feature for collections. See the tutorial for more information on how this fetch mode works.
A lot of the points mentioned in the Best Practices chapter will also positively affect the performance of Doctrine.
See Best Practices