Bug #30082 dynamic updating of backend server list
Submitted: 26 Jul 2007 17:52 Modified: 4 Jun 2009 12:53
Reporter: Laurentiu Badea Email Updates:
Status: Verified Impact on me:
Category:MySQL Proxy Severity:S4 (Feature request)
Version: OS:Any
Assigned to: Assigned Account CPU Architecture:Any
Tags: admin, backend, dynamic, integration, replication

[26 Jul 2007 17:52] Laurentiu Badea
I've noticed that MySQL Proxy supports retrieving its internal configuration via SQL. It would be really nice if this configuration, or at least parts of it, could be updated via the same mechanism.

The idea is to be able to change the backend servers dynamically from an external replication monitoring program. I realize it can probably be done in LUA but the monitor wouldn't be in LUA itself so it would still need to communicate with the Proxy in some way, might as well be in a known fashion (SQL). This may well become a possible common usage scenario for the Proxy so it's worth implementing at some point. The reasons for being able to update the backend list on-the-fly include:

- pick the most up-to-date servers, avoiding slaves that are lagging. Even for reads, where you want to read the freshest data;

- with read/write splitting, select the Write backend based on predefined algorithms that take into account replication state (monitored externally);

- synchronize a set of Proxy servers so they use the same Write backend after a backend failure;

- implement any number of server selection algorithms tightly integrated with the application using the database. Being able to query backend usage stats from the Proxy (queries, times, active etc) would also be useful in this context.

forum link: http://forums.mysql.com/read.php?146,164065

How to repeat:
[4 Jun 2009 12:53] Kay Roepke
Thank you for your feature request.

Functionality of this type will be considered for inclusion in a future MySQL Proxy version.