Cache and Session Storage: The Difference
Cache and session storage have subtle differences and those differences are going to be discussed in here, as many of you are quiet unaware of it. The redis on shared hosting, in-memory database, is extensively utilised in for both session store and caching scenarios.
What is Cache?
Cache is a place where applications can store their data for serving the future request much faster. Ram is the location where cache storage is placed and it also has latency of sub mili second. For improving performance all you have to do is just take the help of cache which can happen almost everywhere.
What is Considered Also Cashing Is the Dynamic Programming
In life cycle of data fetch, the first thing that is looked for by the application is the data in the cache. In case a hit is found, that is there is the existence of data inside the cache, the data is served almost instantly. However, if there is a miss that is if there is no data in the cache then it is best to take from a permanent store and a copy of which is kept in the cache, in the process the data is served to the consumer. So whenever there is any request in the future, data is already present in the cache and show service is much faster. The data, in the time of being updated by the application, automatically updates the permanent store as well as the cache.
The scenarios in which various clients request the exact same data repetitively for a specific period of time, this life circle works miracles.
The data is stored in the level of application and not in the level of the user and this information should be always noted. Due to this the data which is stored inside the cache can be shared among the clients easily. There are multiple examples of data which are quite often kept inside the cache namely,
- static HTML pages
- style sheets
Session Store: Definition
Against a unique session ID, data could be stored for individual users in a much easier way and thus sessions were incepted. State information between the multiple page requests can be persisted through this. In a general scenario, session IDs would be first sent to the Session Storage cookies and from there to the browsers. This ID is utilised for the retrieval of any kind of existing session data.
Since their request as well as response cycles are stateless, angular session storage are very handy and beneficial to be used. They are considered stateless as neither the server nor the client inherently store even 1% of information between the various kinds of requests. During the time of a response making a requesting user agent, the life cycle of a request or response gets over. Here the software, like a native application or a browser is user agent which represents the clients on a device, for example it is like a browser tab on a PC, an application of smartphone or even a refrigerator. Association of one to one with a cookie or access token is done here.
It is utilised for keeping a track of the user and their related information. For example if the client has created an application which requires the users to login in order to get the access of a particular content, then the user will require to provide the right username as well as the attached password, which will enable the user to be redirected to the exact page that could be accessed by only logged in users.
Then if you have ascertain page which shows the private information of this logged in user, which had been previously fed in the application, however you reach that page, what will be the process through which the server will fetch the information we are the database since it has no idea who is the current user? It also must be remembered that HTTP is a protocol that is stateless.
So Session helps here like redis pricing, Redis. Once the user logs into the application, at the server you create a session for this user. The most important of them, the user’s unique identifier. One could use this ID to fetch information from the database until the user is logged in. Invalidate the session once the user logs out. Here the cycle terminates. The server no longer knows this user.
With Redis, a popular database ideal for both cache and session store use cases, delivering both the high-availability required for caching and session store scenarios as well as the durability needed for session store with in-memory replication.
In this design, the application layer accesses and maintains the data in the cache. Therefore, all the sessions running inside the application access the same data stored in the cache.