Eons ago now (circa 2009/2010 I think), when working on Pornhub we switched from memcached to Redis for a few reasons:
- memcache had little to no observability, it made debugging cache issues a nightmare. Redis on the other hand is a dream to work with on that front, from the cli that is well thought out to the fact you can copy the db file to your machine and go at it, it's just a much better developer experience.
- Data structures, Redis' lists, hashes and sets meant we could represent a lot of a stuff as is in cache with no need for costly serializing. It also meant the data layer code was simpler than the memcached equivalent.
- Built in pub/sub, we used it for tons of stuff and the fact it came built in was big as prior to that we had to provision specific stacks to get the same functionality (and it wasn't has nice to use.
memcache has its use but for the little advantages it gave (perf wise) Redis just buried it in developer experience.
- memcache had little to no observability, it made debugging cache issues a nightmare. Redis on the other hand is a dream to work with on that front, from the cli that is well thought out to the fact you can copy the db file to your machine and go at it, it's just a much better developer experience.
- Data structures, Redis' lists, hashes and sets meant we could represent a lot of a stuff as is in cache with no need for costly serializing. It also meant the data layer code was simpler than the memcached equivalent.
- Built in pub/sub, we used it for tons of stuff and the fact it came built in was big as prior to that we had to provision specific stacks to get the same functionality (and it wasn't has nice to use.
memcache has its use but for the little advantages it gave (perf wise) Redis just buried it in developer experience.