Comments - MaxScale Customisation - Filter, Routing of Clients, "Sticky" Statements
Content reproduced on this site is the property of its respective owners,
and this content is not reviewed in advance by MariaDB. The views, information and opinions
expressed by this content do not necessarily represent those of MariaDB or any other party.
The regexfilter does not support mathematical operations. It uses the POSIX regular expression syntax: http://pubs.opengroup.org/onlinepubs/009696899/basedefs/xbd_chap09.html
Retrieving the master server is doable from inside a filter, the servers used by the service are accessible to the filter through the shared session data.
Right now there is only experimental support for scripting interfaces to MaxScale. The Luafilter on the GitHub branch 'luafilter' has a filter which supports scripts written in the Lua language: https://github.com/mariadb-corporation/MaxScale/blob/luafilter/server/modules/filter/luafilter.c
If a master server dies, MaxScale will detect this when the monitor modules try to query the server for status. Connections to this server are severed if they are still open and an error is sent to the client. Currently the session is closed if the master server dies while it is still open even though reads could still be accepted.
JOIN queries over multiple servers is not something MaxScale currently supports. I recommend looking at the Spider storage engine for MariaDB: https://mariadb.com/kb/en/mariadb/spider/