Caching and You and You and You and You...

A run through of what caching is, when to use caching, some common caching engines, and how to use caching in common PHP frameworks.

Transcript

1. Caching and You and You and You and You... Justin Yost Lead Software Engineer Wirecutter CC BY-NC 4.0 Justin Yost 1
2. Caching - What is it? • Storing data for faster access in the future. CC BY-NC 4.0 Justin Yost 2
3. Caching - What data? • SQL Results • HTML • Transient Storage CC BY-NC 4.0 Justin Yost 3
4. Caching - SQL • Store a common SQL result for a complex operation • Doing math for a running average, only need a new result every 15 minutes? • Determining the range of dates a business is open? • Determining the edges of a spatial data set? CC BY-NC 4.0 Justin Yost 4
5. Caching - HTML • Cache whole static pages • Cache a subset of pages that's used across the site; footer, header, etc. CC BY-NC 4.0 Justin Yost 5
6. Caching - Transient Storage • Cache and increment the number of failed login attempts CC BY-NC 4.0 Justin Yost 6
7. Caching Engines • Redis • Memcached • File • Database • There's others at different levels for different problems (Varnish, etc) CC BY-NC 4.0 Justin Yost 7
8. Caching Engines • Stores data basically in a Key/Value Pair Combination (in- memory) CC BY-NC 4.0 Justin Yost 8
9. $key = inputsToAKey($inputs); if (isCached($key)) { $sqlResults = getFromCache($key); } else { $sqlResults = reallyHardProblem($inputs); cache($sqlResults, $key, $dateTimeToExpire); } CC BY-NC 4.0 Justin Yost 9
10. Tradeoffs • Reading vs Writing • Staleness vs Freshness • Speed vs Complexity CC BY-NC 4.0 Justin Yost 10
11. Memcached • Simpler and smaller • More efficient at storing small, staticy subsets of data • Multi-threaded (beefier servers can add more scale) • Typically better at reads over writes. CC BY-NC 4.0 Justin Yost 11
12. Redis • Stores more complex data sets • Replication support • Transactional support • Pub/Sub support • Act as a queue server CC BY-NC 4.0 Justin Yost 12
13. Caching in Laravel Cache::put('key', 'value', $seconds); // put at key, value for x seconds Cache::forever('key', 'value'); // put at key, value forever Cache::forget('key'); // remove value at key Cache::has('key'); // does a value at key exist Cache::get('key', 'default'); // get the value at key, with a default option CC BY-NC 4.0 Justin Yost 13
14. Caching in Symfony - non PSR 6 $value = $cache->get('key', function (Symfony\Contracts\Cache\ItemInterface $item) { $item->expiresAfter($seconds); return 'value'; }); $cache->delete('key'); CC BY-NC 4.0 Justin Yost 14
15. Caching - PSR 6 $item = $cache->getItem('key'); $item->set('value') $cache->save($item); $item = $cache->getItem('key'); $item->isHit(); 'item' = $item->get(); $cache->deleteItem('key'); CC BY-NC 4.0 Justin Yost 15
16. Caching - CakePHP Cache::write('key', 'value'); Cache::read('key'); // false on no data Cache::remember('key', function(){ return 'value'; }); Cache::delete('key'); Cache::readMany(['key1', 'key2']); Cache::writeMany(['key1' => 'value1', 'key2' => 'value2']); Cache::clearGroup('group1', 'group2'); CC BY-NC 4.0 Justin Yost 16
17. Caching - Phalcon $value = $cache->get('key'); // null on no data $cache->exists('key') $cache->save('key, 'value', $seconds); CC BY-NC 4.0 Justin Yost 17
18. Thanks Questions? • twitter.com/justinyost • github.com/justinyost • justinyost.com • linkedin.com/learning/instructors/justin-yost CC BY-NC 4.0 Justin Yost 18