inanzzz | Using doctrine APC caching with QueryBuilder in symfony

This tutorial is based on native doctrine/cache package. First of all, APC must be enabled in php.ini file. Example below will show us how to use APC cache to increase application performance. For more information, you can read Doctrine Caching chapter and Alternative PHP Cache.

Facts

metadata_cache_driver: Doctrine metadata stores information about entity structure, relations, validation rules so on which may come from annotations, YAMLs or XML definitions. When activated, it would prevent parsing class metadata in each request. This would provide performance but at same time, if we change anything in class metadata definitions, our application would still use old version from the cache so in such case we should manually clear the cache!

query_cache_driver: Doctrine2 uses DQL to generate SQL queries. Whether we use plain SQL query strings in DQL or QueryBuilder in repositories, Doctrine generates SQL query for each request. Enabling this option won't put the DB query results in cache automatically so we have to manually tell it to do so in QueryBuilder. If we change our SQL query strings or QueryBuilder definitions, our application would still use old version from the cache so in such case we should manually clear the cache!

result_cache_driver: Enabling this option won't put the DB query results in cache automatically so we have to manually tell it to do so in QueryBuilder by setting its lifetime and ID. If we change data in DB our application would still use old version from the cache so in such case we should manually clear the cache!

Configurations

config_dev.yml

doctrine:
    orm:
        metadata_cache_driver:
            type: apc
        query_cache_driver:
            type: apc
        result_cache_driver:
            type: apc

php.ini

extension=apc.so
apc.enabled=1
apc.shm_segments=1
apc.shm_size=32M
apc.cache_by_default=1
apc.stat=1
apc.rfc1867=1
apc.enable_cli=1

Testing

You can use browser based application APC-Admin to monitor caching activities.

Query base

public function findAll()
{
    $qb = $this->createQueryBuilder('l')
        ->select('l, t, p')
        ->innerJoin('l.team', 't')
        ->innerJoin('t.player', 'p')
        ->orderBy('l.name', 'ASC')
        ->addOrderBy('t.name', 'ASC')
        ->addOrderBy('p.name', 'ASC')
        ->getQuery();

    $qb = $qb->getResult();

    return $qb;
}

You must add line below to the query to enable query caching.

...
->getQuery()
->useQueryCache(true);

You must add line below to the query to enable result caching.

...
->getQuery()
->useResultCache(true, 60, 'my_unique_cache_id');

No cache

Millisecond MB
2728        42.2 (*)
1050        28.5
650         28.5
664         28.5
669         28.5

Cached files: 0 KBytes
Cached variables: 0 KBytes
Cache variable name: NA

metadata_cache_driver enabled

Millisecond MB
3312        40.2 (*)
1462        28.2
698         28.2
670         28.2
681         28.2

Cached files: 9.2 KBytes
Cached variables: 9.2 KBytes
Cache variable names:
sf2orm_default_f2fbb5259b59469e8f50fbd0bfaef6747e168f1e5a445e5cb5812f652c835bf9[Application\BackendBundle\Entity\Player$CLASSMETADATA][1] (Expires: NA)

query_cache_driver enabled

Millisecond MB
3054        40.2 (*)
651         26.5
632         26.5
648         26.5
635         26.5

Cached files: 3.8 KBytes
Cached variables: 3.8 KBytes
Cache variable names:
sf2orm_default_f2fbb5259b59469e8f50fbd0bfaef6747e168f1e5a445e5cb5812f652c835bf9[07aa386f36aa0c503519f5baf6076bda][1] (Expires: NA)

result_cache_driver enabled

Millisecond MB
3301        40.8 (*)
646         28.8
642         28.8
696         28.8
627         28.8

Cached files: 346.8 KBytes
Cached variables: 346.8 KBytes
Cache variable names:
DoctrineNamespaceCacheKey[sf2orm_default_f2fbb5259b59469e8f50fbd0bfaef6747e168f1e5a445e5cb5812f652c835bf9] (Expires: never)
sf2orm_default_f2fbb5259b59469e8f50fbd0bfaef6747e168f1e5a445e5cb5812f652c835bf9[my_unique_cache_id][1] (Expires: 60 sec)

All three enabled

Millisecond MB
1854        41.0 (*)
628         26.8
636         26.8
632         26.8
622         26.8

Cached files: 358.5 KBytes
Cached variables: 358.5 KBytes
Cache variable names:
sf2orm_default_f2fbb5259b59469e8f50fbd0bfaef6747e168f1e5a445e5cb5812f652c835bf9[07aa386f36aa0c503519f5baf6076bda][1] (Expires: NA)