一个用于多个客户端的大型MySQL数据库

Question

NB This is not another "One large DB or several small DBs" question.

Using one large MySQL database for several clients (same structure, etc), with a user column to separate the clients, is it possible limit the table access for the user with the matching user column`?

I'm not too familiar with Microsoft's SQL Server, but I read something about "multi-tenant data architecture" that seemed to offer this.

Does MySQL have something similar?

Answer 1

I would recommend against having 1 large DB for all your clients for multiple reasons:

1. I've worked at a startup where the AWS instance for one of our DB just gave away (for no fault of ours). Let's just say that was a hectic day for everyone in the office. If this happens to your ONLY DB, how are you going to ensure customer satisfaction? How are you going to maintain a robust system? There's a saying that at google, a server goes does every 2 seconds. While that may not happen when you're starting off, know that you're not immune from your servers failing. Sharding your DB into multiple instances is a good way of hedging against a major failure.
2. If you have many transactions, your thread pool is always going to get locked up. You don't want this because it's going to increase the amount of time it takes to perform CRUD operations on your database, which in turn is going to effect customer satisfaction.

A better mult-tenant archticture you want to have is:

1. Have 1 master DB for every client (maybe every 2 clients at the beginning), then have slaves for every master DB you have. Now you can perform all your writes on the slaves and perform all your reads off of the master. As long as you keep your DB's in sync, this is the best way to ensure your thread pool maintains availability and quickly performs all the transactions.

Here's a great article titled " High Availability, Load Balancing, and Replication ," which will give you a great primer into building a robust multi-tenant system. I would also recommend reading the articles on High Scalability

Please let me know if you have any questions!

Answer 2

MySQL has table-level and column-level privileges, but not row-level privileges.

The closest thing would be to define a VIEW through which a user accesses the table. The view has privilege to access to the base table, and each user has privileges to access the view.

Define the view to restrict access to the current user.

mysql> create table base (user varchar(16), x int);
mysql> insert into base values ('root@localhost', 123), ('bill@localhost', 456);
mysql> create view v as select * from base where user = USER() with check option;
mysql> select * from v;
+----------------+------+
| user           | x    |
+----------------+------+
| root@localhost |  123 |
+----------------+------+