NoSQL technology usage scenarios:
In our daily development, all are using the database to store data, due to the general system tasks typically do not exist in the case of high concurrency, so this seems to be no problem, but once the needs of large amount of data involved the system such as some commodity buying scenarios, or home visits moment when the larger, single-use database to store the data because of the speed-oriented disk, disk read / write slower problems serious performance drawbacks, the moment thousands of request comes in, the system needed to complete thousands of read / write operations in a very short period of time, this time more often than not be able to withstand the database, the database system is extremely easy to cause paralysis, eventually leading service downtime serious production problems.
In order to overcome the above problems, projects often introduce NoSQL technology, which is a memory-based database, and provide some persistence function.