High load projects on Symfony Maksym Moskvychev [email protected] 

About speaker 

Agenda Network design Framework abilities to increase performance Architecture principles & examples Cache abilities Tips to save memory 

Network design 

Network design of typical PHP application PHP node Session storage Database cluster MySQL node MySQL node MySQL node Load balancer PHP node Reverse proxy PHP node PHP node Internet Media storage 

Master / slave database connection in Symfony Master node Slave node Slave node Slave node Load balancer Read/write connection Read connection Default entity manager Read entity manager 

Session storage allows to share sessions between PHP nodes 

Media storage allows to sha e use s’ files between PHP nodes 

Reverse proxy is.. • Application firewall • Cache system • Load distributer • SSL encryption system 

AppCache in Symfony • Can be turned on in app.php file • Lightweight alternative of Varnish • Useful for development only 

Framework abilities to increase performance 

Use ACP cache whenever it possible • Enable APC cache in PHP settings. • Cache class autoloader with APC. • Turn on Doctrine query cache with ACP 

Architecture principles & examples 

Storing logic in SQL queries Logic in PHP classes Logic in SQL queries + easy to implement + easy to maintain + complex logic could be split into classes + could be covered with unit test + fast for batch operations VS 

Admin area Storing logic in SQL queries Product publication logic (method in repository) ->joinLeft(… Front end Rest API Query in SonataAdminBundle Query for frontend Rest controller 

Pre-loading data in Doctrine • By default Doctrine loads data from related entities at the moment getter is used. • There is a possi ility to do load all relatio s data in one query. $query->joinLeft(‘product.category’); 

Personalization & full page cache Full page cache adds some limitations, because most requests never reach real server - There is no user sessions There is JavaScript There are headers, cookies There are IFrames There are ESI tags 

Personalization & full page cache Some page JavaScript Google analytics & another tracking systems Recently seen pages. Data stored in Cookies User menu in IFrame. Cached by private cache Page itself. Cached by public cache 

Cache abilities 

Caching in web application Http cache • Full page cache • Gateway cache • PHP accelerator • Reverse proxy Query result cache • APC • File system • Memory Other methods 

Http cache Unified standard for caching, defined in HTTP protocol Cache communicates with application via HTTP headers and status codes Expiration and validation caching models Fully supported by Symfony HTTP Foundation component 

Expiration model in HTTP cache Reverse proxy PHP node Internet Hey, this response would be OK for next 2 hours . Re uest to /contacts page Reverse proxy Internet 2. Re uest to /contacts page within hou s 

Validation model in HTTP cache Reverse proxy PHP node Internet Hey, this response has ETag d54sd65yf6cytfrtfg7w4fgy . Re uest to /a ticle page MySQL node Reverse proxy PHP node Internet Gi e e /arti le1 FYI: I know response for ETag d54sd65yf6cytfrtfg7w4fgy 2. Re uest to /a ticle page MySQL node Yes, this is exactly d54sd65yf6cytfrtfg7w4fgy • Fetch only hash of article • Fetch all data for article • Fetch only hash of article 

Caching query results in Symfony 1. Choose one of existing caching providers: APC, memory (arrays), file system, etc.. 2. “et result query cache provider duri g uildi g a query 3. Choose and set cache lifetime during building a query. 

Tips to save memory 

Turn off SQL logger. In debug mode it stores in memory information about all executed queries. 1 

Clear entity manager from time to time $entityManager->clear() 2 

Flush garbage collector inside of long loops gc_collect_cycles() 3 

Use pagination to fetch huge amount of data Use few queries with limit/offset instead of one query for all data. 4 

Typical scheme of console command in Symfony Turn off SQL logger Fetch batch of data Apply some logic to each data row Clear entity manager Flush garbage collector 

Q & A Maksym Moskvychev [email protected]