How do I use redis in my application?

[Percepticon77]

I want to cache part of my application to make it faster. The database I use is MySQL. How do I know what to cache in redis?

Should I be caching MySQL results? Or the output we send to the client?

What else can I use redis for to improve application performance?

[jjay2024]

Sure thing, caching with Redis is a great move for speeding up your app, especially when you're hitting a MySQL database a lot.

First up, find out which parts of your database interactions are dragging their feet. Are there specific queries that take forever? Maybe there's data that gets requested a lot that doesn't change very often? That's your target for caching.

If certain queries are both slow and common, cache their results. For example, if you’re frequently fetching the details of a product that rarely changes, stash that in Redis.

Sometimes it makes sense to cache the final response you send to the client. This is especially useful if you're doing a lot of processing or aggregating multiple data sources before responding.

Basically, with Redis, you're looking to reduce the load on your MySQL database and speed up response times by caching heavy or frequent queries and outputs. Dive into your app’s performance metrics to see where the bottlenecks are and start experimenting with caching those parts. It’s usually a bit of trial and error to find the sweet spot, but it can make a huge difference!

[developercat]

Use Redis to cache your queries. You can use MySQL query logs to find the most expensive queries and then cache the results of those queries in Redis. Set the expire time. Here is an example function.

It checks redis to see if the cached results exist and if it's found it returns it. If not, it will fetch from MySQL and store the results with an expiry.

<?php // Redis Connection $redis = new Predis\Client(); // MySQL Connection $mysqli = new mysqli('your_db_host', 'your_db_user', 'your_db_password', 'your_db_name'); function get_data_from_cache_or_mysql($sql_query) { $redis_key = 'query_cache:' . md5($sql_query); // Unique key per query if ($redis->exists($redis_key)) { $result = unserialize($redis->get($redis_key)); return $result; // Return from cache } else { $result = $mysqli->query($sql_query); $data = $result->fetch_all(MYSQLI_ASSOC); $redis->set($redis_key, serialize($data)); $redis->expire($redis_key, 600); // Expire after 10 minutes (600 seconds) return $data; } } $sql_query = "SELECT * FROM users WHERE post_count > 50"; $users = get_data_from_cache_or_mysql($sql_query);