Silverstripe at scale - design & architecture for silverstripe applications
- 2. Design & Architecture for Silverstripe applications Silverstripe at Scale
- 3. About me Brett Tasker Principal Platform Engineer & Security Specialist at Silverstripe Ltd. You may recognize me from... ● Silverstripe Docker images (brettt89/silverstripe-web) ● How to build a local development environment (blog) ● Garbage Collection module (module) ● Community Slack (Brett Tasker)
- 4. Overview ● Introduction ● Architecture ● Performance ● Code Design ● Wrapping it up
- 5. Scalability is the property of a system to handle a growing amount of work by adding resources to the system. - Wikipedia “ ”
- 8. Load Balanced Architecture & Design
- 10. Web Servers
- 11. ● Apache Module ● Fork Driven ● Memory Usage ● Easy Setup mod_php PHP Handlers
- 12. ● Separate Process ● FastCGI ● Event Driven ● FPM FastCGI / FPM PHP Handlers
- 13. Performance
- 15. ● PHP executions are single threaded ● Each PHP execution can only use a single core ● Cores vs Frequency ● Webserver services are multi-threaded ● Database services are multi-threaded ● Microservice Architecture CPU performance
- 17. PHP APCu ● User cache ● Code Controlled ● Included in Silverstripe CMS ● Local shared memory ● Default shm size 32M
- 18. OPCache ● Bytecode cache ● Built into PHP Engine ● Stores precompiled PHP ● Included in Silverstripe CMS ● Local shared memory ● No Garbage Collection ● Restart = Rebuild of cache
- 19. Redis ● User cache ● Key Value store ● TCP / Shared ● Application Memcached ● User cache ● Key Value store ● TCP / Shared ● Application
- 22. InnoDB ● Table & Index data cache ● Buffers & Flushing ● Buffer Pool ○ Lookups ○ 60%-80% RAM ● Log Buffer ○ Transactions ● Log File
- 24. Query Caching ● Result set cache ● Deterministic Queries ● Does not support: ○ Subqueries ○ Temporary Tables ● Larger != Better
- 26. ● Assets module requires .htaccess ● Does not work OOTB with Nginx ● SS_PROTECTED_ASSETS_PATH Apache Dependency
- 27. ● Used by default for CMS ● Adds _Versions tables for each DataObject ● Manipulates SELECT queries to JOIN _Versions ● Uses subqueries ● No Garbage Collection ● Only use what you need ● Consider disabling Versioning on DataObjects Versioned module
- 28. ● Dynamic generation of SQL queries ● Many_many relationships ● Subqueries / Large datasets ● Multiple smaller ORM executions ORM Queries
- 29. ● Single DB connection per PHP execution ● PHP concurrency == DB concurrency ● Low Database connections is bad ● Resource stampede ● DB Connection closes at end of PHP execution Database Connections
- 30. ● HTML & Parameter Substitution ● Often large cache datasets ● Not suitable for In-Memory caching ● Filesystem caching works well Partial Caching
- 31. Code Design
- 32. DefaultCacheFactory ● Filesystem ● APCu ● OPCache ● Chain Cache
- 33. Filesystem Caching ● Files on Disk ● Serialization & JSON format ● Filenames = Cache Key ● One cache object per file ● No Garbage Collection
- 34. APCu Caching ● Memory caching ● Silverstripe CMS uses ChainCacheAdapter for APCu ● Fallback to Filesystem caching through ChainCacheAdapter ● Cache writes are applied to all layers of ChainCacheAdapter ● Potential waste of resources OOTB
- 35. OPCache ● Memory caching (Bytcode cache) ● Uses Filesystem caching architecture ● PHP Arrays in .php files ● Uses PHP “Include” function for loading ● Stored in OPCache precompiled cache data
- 36. What user caching do I use?
- 37. DO NOT USE OPCACHE FOR USER CACHE
- 41. Purpose of Caching ● Reduce Expensive Operations ● Do you need to cache that data? ● DataObjects VS Array ● Cache keys ● Caching for Value
- 42. Code Duplication & Vendor Dependencies ● Composer autoloader ● All PSR-4 defined content is loaded by Autoloader ● Duplicated code ● Unused vendor dependencies ● Reduce vendor overhead for more resources
- 43. Generators & Looping ● Large Datasets ● Memory Exhaustion ● ORM does not use Generators by default ● getGenerator method is available on DataList (ORM) ● Yield helps reduce resources requirements
- 44. Unset vs Null ● PHP does have ‘true’ garbage collection ● Unset flags memory allocation for re-use ● Value setting requires adjustment of memory allocation ● Unset faster than setting to NULL ● Iterations / Loops
- 45. Unset vs Null
- 46. Wrapping Up
- 47. Summary ● Load Balanced / Microservices ● Mod_php VS FastCGI ● Resource Relationships ● Bottlenecks / Performance ● Balancing speed and resources
- 48. Thank you!