You have replication configured, which consists of one master and one slave on different hosts with an asynchronous replication channel between them.
Your goal is to decrease the amount of data that is transferred between these two hosts.
It is confirmed that the slave instance does not need to have data from the example database.
Which replication filter contributes to your goal?
To decrease the amount of data transferred between the master and slave, you should configure the replication filter on the master using --binlog-ignore-db=example. This ensures that the data from the example database is not written to the binary log on the master, thereby preventing it from being sent to the slave at all. This approach reduces the data transferred over the replication channel effectively.
answer is A. Its not B because you can use database1 and still insert into another table on another database. The wild card makes it so if you use another database but insert into this table from another database, it won't happen.
https://www.alibabacloud.com/forum/read-387
For example, if --replicate-ignore-db=nonreplicated is configured on the replica server, the following sequence of statements causes the GRANT statement to be ignored, because the default database nonreplicated is in effect:
With B, you can still replicate. For example, use DB2; insert into DB1.table1 values (1); Things in DB1 was still inserted in replication because you were using DB2. ignore db just ignores the base database you are in, not the statement.