BoUk

There are deffinitely different methods for implementing pageview counters. Considering some external service such as <a href="https://jetpack.com/" rel="nofollow ugc">Jetpack</a> or <a href="https://analytics.google.com/" rel="nofollow ugc">Google Analytics</a> is surely a good option, but there may be scenarios where you may want to handle this just by yourself and have everything more under control.
Since it’s very common to utilize some caching mechanism to improve your site’s performance, implementing counter directly on PHP level wouldn’t work reliably as counter would be barely incremeneted due to the caching. Better solution would be to use WordPress way of triggering AJAX requests and increment pageview counters anytime page is loaded, no matter if served from cache or not.
When we start to think on bigger scale though, we find tradional WP AJAX implementation quite resources heavy as well. This plugin uses slightly more complicated method to increase counters, but it’s very lightweight. In a nuthsell, counters are stored ‘outside’ of WordPress ecosystem into some fast storage such as Memcached or Redis. Then there’s implemented re-occuring cron task on WordPress level, which regularly checks for new counters and store its values as postmeta for each respective post.
Plugin utilizes <a href="https://www.phpfastcache.com/" rel="nofollow ugc">PhpFastCache library</a> which allows to store data into many types of back-ends. See their <a href="https://github.com/PHPSocialNetwork/phpfastcache/blob/master/docs/DRIVERS.md" rel="nofollow ugc">documentation</a> for more details. This feature allows you to choose any back-end depending on your hosting provider.
This plugin comes preconfigured with file-based storage, which should work on any hosting environment, but for higher traffic sites you may want to consider in-memory storage such as MemcacheD.
Whole principle and idea is described in following <a href="https://www.bouk.info/efficient-handling-of-ajax-requests-on-wordpress-platform/" rel="nofollow ugc">article</a> published on my blog.

PageViews Counter

Implement your own pageviews counter in efficient way, using different backend storages such as MemcacheD or Redis.

PageViews Counter vs Koko Analytics – Privacy Friendly Statistics for WordPress