PSR-6 & Symfony Cache: fast by standards

After several months of discussion, the PHP-FIG (PHP Framework Interop Group) published the PSR-6. Its goal is to enable interoperability between caching systems implementations - a mandatory aspect to improve performance in your applications. At this conference, we will see the benefits and limitations of PSR-6, we will discuss the various existing cache solutions (Doctrine, Stash, php-cache), and I will present the new Symfony 3.1 Cache component and its upcoming improvements in version 3.2.

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1. PSR-6 & Symfony Cache
   fast by standards
   #Symfony_Live
   @nicolasgrekas
   

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2. @nicolasgrekas
   # Symfony_Live
   

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3. #Symfony_Live @nicolasgrekas
   

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4. #Symfony_Live @nicolasgrekas
   

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5. #Symfony_Live @nicolasgrekas
   

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6. “There are only two hard things
   in Computer Science:
   - cache invalidation
   - and naming things.”
   -- Phil Karlton
   

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7. PSR-6
   Caching Interface
   Draft: Sept. 2013
   Final: Dec. 2015
   

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8. #Symfony_Live @nicolasgrekas
   • A common interface for basic and
   intermediate-level caching needs.
   • Allow for multiple independent extensions
   without collision.
   PSR-6 Goals
   

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9. #Symfony_Live @nicolasgrekas
   • Architectural compatibility with all existing cache
   implementations.
   • Advanced caching features such as namespacing
   or tagging.
   PSR-6 Non-Goals
   

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10. #Symfony_Live @nicolasgrekas
    • doctrine/cache 16.8M
    • sonata-project/cache 1.3M
    • zendframework/zend-cache 1.1M
    • illuminate/cache 0.5M
    • tedivm/stash 0.4M
    PSR-6 Prior-art on Packagist
    

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11. #Symfony_Live @nicolasgrekas
    PSR-6 Concerns
    

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12. #Symfony_Live @nicolasgrekas
    • Crippled with “Bylaws”
    • Not always representative
    • Strategic hijacking
    • Way too much noise/overhead
    • Mission is unclear
    PHP-FIG Weaknesses
    

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13. PHP-FIG Strength
    Standards!
    Let’s do with!
    

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14. #Symfony_Live @nicolasgrekas
    PSR-6 CacheItemPoolInterface
    

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15. #Symfony_Live @nicolasgrekas
    PSR-6 CacheItemInterface
    

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16. #Symfony_Live @nicolasgrekas
    PSR-6 Example #1
    

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17. #Symfony_Live @nicolasgrekas
    PSR-6 Example #2
    

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18. #Symfony_Live @nicolasgrekas
    • CacheItemInterface instances are not
    interoperable
    • Restricted characters for keys
    • false as error reporting
    • No atomicity/transactionality
    • Lazyness is unspecified
    PSR-6 Edge-cases
    

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19. #Symfony_Live @nicolasgrekas
    • See on Packagist
    https://packagist.org/providers/psr/cache-implementation
    • Stash PHP – stashphp.com
    • PHP Cache – php-cache.com
    • and …
    PSR-6 Implementations
    

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20. Welcome
    Symfony Cache
    

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21. #Symfony_Live @nicolasgrekas
    • Be the most powerful PHP caching library
    • A strict PSR-6 implementation
    • Following Symfony’s quality processes*
    • Just the bare minimum to be fast by default
    * Thanks "cache/integration-tests"!
    Symfony Cache Goals in 3.1
    

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22. #Symfony_Live @nicolasgrekas
    • ApcuAdapter
    • ArrayAdapter
    • FilesystemAdapter
    • RedisAdapter
    • …it’s up to you to add more
    Base Symfony Cache Adapters
    

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23. #Symfony_Live @nicolasgrekas
    • AbstractAdapter
    • ChainAdapter
    • DoctrineAdapter
    • ProxyAdapter
    • + DoctrineProvider
    Special Symfony Cache Adapters
    

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24. #Symfony_Live @nicolasgrekas
    Symfony Cache CacheItem
    

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25. #Symfony_Live @nicolasgrekas
    Symfony Cache AbstractAdapter
    

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26. #Symfony_Live @nicolasgrekas
    Doctrine 834.863 items/ms
    PHP Cache 313.334 items/ms
    Stash PHP 55.346 items/ms
    Symfony 533.366 items/ms
    Bench Symfony Cache
    

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27. #Symfony_Live @nicolasgrekas
    Doctrine 705.001 items/ms
    PHP Cache 362.477 items/ms
    Stash PHP 153.803 items/ms
    Symfony 845.910 items/ms
    Bench Symfony Cache
    

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28. Symfony Framework
    Wiring
    

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29. #Symfony_Live @nicolasgrekas
    Symfony Framework Concepts
    Front 1 - APCu Front 2 - APCu
    Redis
    Pool 1: Code Annotations
    Pool 2: Validation
    Pool 3: SQL results Pool 4: API responses
    

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30. #Symfony_Live @nicolasgrekas
    • « cache.app » for model sourced items
    o Defaults to filesystem, change it to Redis
    • « cache.system » for code sourced items
    o Defaults to APCu+filesystem chain
    Symfony Framework Services
    

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31. #Symfony_Live @nicolasgrekas
    Symfony Framework Semantic Config
    

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32. #Symfony_Live @nicolasgrekas
    Symfony Framework Semantic Config
    

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33. #Symfony_Live @nicolasgrekas
    Symfony Bundle Config
    

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34. #Symfony_Live @nicolasgrekas
    Wrap Symfony Cache as Doctrine Providers
    

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35. What’s next?
    

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36. #Symfony_Live @nicolasgrekas
    • Cache warming-up
    o Regeneration Before Expiration
    o Desynchronized Cache Misses
    o Stampede Protection
    Beyond PSR-6
    

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37. #Symfony_Live @nicolasgrekas
    • Cache invalidation
    o Hierarchy?
    o Tagging?
    Beyond PSR-6
    

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38. #Symfony_Live @nicolasgrekas
    • New adapter: PDO/DBAL, PHP array/file, Null
    • Tags based invalidation
    o $cache->invalidateTags($tags);
    • Hierarchical invalidation
    o $cache->withContext($contextChecksum);
    • cache:pool:clear command
    • Warm-up Validator, Serializer, etc.
    • Deprecate per components *CacheInterface
    Symfony 3.2
    

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39. #Symfony_Live @nicolasgrekas
    • Serve stale items while refreshing?
    • Desynchronized Cache Misses?
    • Add a profiler panel with hits/misses?
    • …add your ideas here
    Symfony 3.3?
    

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40. Merci !
    #Symfony_Live
    @nicolasgrekas
    

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