MySQL middleware research (Atlas, cobar, TDDL), sub-database sub-table plugin

http://www.guokr.com/blog/475765/

alibaba.cobar
Cobar is a relational data distributed processing system developed by Alibaba (B2B) department. It can look like traditional The database also provides you with massive data services. So specifically why do we use it, or what can cobar do? The following are some problems that will exist in our business operation:
1. With the rapid increase of the data volume and access volume of the database, the data needs to be split horizontally to reduce the pressure on a single database, and it needs to be efficient and relatively transparent to mask out the details of the horizontal split.
2. To improve the availability of access, the data source needs to be backed up.
3. Data source availability detection and failover.
4. The high concurrency of the foreground causes too many connections to the background database, which reduces the performance. How to solve it.
In response to the above problems, there is space for cobar to display its own. The cobar middleware is located between the front-end application and the actual database in the form of a proxy. The open interface to the front-end is the mysql communication protocol. Change the front-end SQL statement and forward it to the appropriate back-end data sub-database according to the data distribution rules, and then combine the returned results to simulate the database behavior under a single database.



TDDL
Taobao has developed the TDDL (Taobao Distributed Data Layer nickname: big head ©_Ob) framework according to its own business characteristics, which mainly solves the application transparency of sub-database and sub-table and data replication between heterogeneous databases. It is a jdbc datasource implementation based on centralized configuration, with functions such as active/standby, read/write separation, and dynamic database configuration.


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