Database caching in RAM?

Question

Database

Hello!
There is a question, for example, on a server there is a software, a project or a website with a database. There are, let's say, a lot of RAM. Many projects hash all site databases into RAM.
Can you explain to me why it does this and what is the profit from this?

Answer 1

Not hashing, but caching.
The result of query execution is cached in memory. To reduce the response time and reduce the load on the database.
In addition, the DBMS has its own cache, with the same purpose. She manages it herself.
For caching, it is preferable to use RAM. Because the speed of accessing data in memory is many times faster than accessing data on disk.