With the comment filter it is possible to define comments that are injected before the actual statements. These comments appear as sql comments when they are received by the server.
[MyComment] type=filter module=comment inject="Comment to be injected" [MyService] type=service router=readwritesplit servers=server1 user=myuser password=mypasswd filters=MyComment
The Comment filter requires one mandatory parameter to be defined.
A parameter that contains the comment injected before the statements. There is also defined variable $IP that can be used to comment the IP address of the client in the injected comment. Variables must be written in all caps.
Example 1 - Inject IP address of the connected client into statements
The following configuration adds the IP address of the client to the comment.
[IPComment] type=filter module=comment inject="IP=$IP" [MyService] type=service router=readwritesplit servers=server1 user=myuser password=mypasswd filters=IPComment
In this example when MaxScale receives statement like:
SELECT user FROM people;
It would look like
/* IP=::ffff:127.0.0.1 */SELECT user FROM people;
when received by server.