6.4.2 DBwriter client

Query-like messages consumed from Rabbitmq by the DBwriter-server are just sent to the database as updates.

Additionally, there is a TCP connection between DBwriter-server and DBwriter-client over which both services let each other know the number of database operations they have performed. By doing so, we could know which database is the most updated one. The one that has performed more DB operations is considered as the Master. Consequently, mastership is informed to the Load balancer so that it can redirect query messages to the corresponding database. By default, at runtime, DBwriter-client is considered as backup.