What are the benefits of a stateless web application?
It seems some web architects aim to have a stateless web application. Does that mean basically not storing user sessions? Or is there more to it?
If it is just the user session storing, what is the benefit of not doing that?
Answer
- Reduces memory usage. Imagine if google stored session information about every one of their users
- Easier to support server farms. If you need session data and you have more than 1 server, you need a way to sync that session data across servers. Normally this is done using a database.
- Reduce session expiration problems. Sometimes expiring sessions cause issues that are hard to find and test for. Sessionless applications don't suffer from these.
- Url linkability. Some sites store the ID of what the user is looking at in the sessions. This makes it impossible for users to simply copy and paste the URL or send it to friends.
NOTE: session data is really cached data. This is what it should be used for. If you have an expensive query which is going to be reused, then save it into session. Just remember that you cannot assume it will be there when you try and get it later. Always check if it exists before retrieving.