What are some ways to reduce mysql database load?

Question

PHP

There is a database and a simple question-answer service, the hoster continually reports that the limit has been exceeded ... Despite the fact that the CPU load is minimal, it does not exceed 5-6% (the database enters for 100).
Are there practices in using some kind of buffer? It can store everything in XML (transfer data from the database to the server and partially load it) up to a certain point, and synchronize once a day, for example.
So far, everything is simple, received the data, prepared a request - executed.

Answer 1

Most often, the problem is that people do not have indexes. It is possible to lower from 100% load sometimes to zero by setting one index

Answer 2

Storing data in XML is a great way to increase server load by up to 300%. This format is not intended for processing (especially for multi-threaded) data, it is suitable for transferring information between systems.
There is a buffer for the database, there are caches, that's all. Do you have indexes on your tables?

Answer 3

if the host is not a server, which means that all sorts of caches are meaningless
, only indexes remain