Accept minimum required GTID

[kirs]

I've been really excited to see 6691a86 and #2120! Thanks for working on this.

I'm opening the issue to discuss a potential feature request. Feel free to close it if you think it's not too relevant.

Given the app that connects to ProxySQL is now able to get current GTID from its MySQL session, we could store that GTID somewhere between requests (maybe in a cookie/web session), and when the browser makes a next request, out web app would know "minimum GTID" that it required to consistently access data.

Could we make a way to signal that minimum GTID to ProxySQL and ask it to route queries to any MySQL host that is >= that GTID?

One way would be to pass it in a magic comment as a part of query (/*+ proxysql_min_gtid=foo */ SELECT ...), but there might be better options.

This would allow to balance queries on all replicas that are caught up until a certain point.

Looking forward to hear your thoughts.

[renecannao]

Hi @kirs ,
If I understand correctly your request, you would like to extend ProxySQL ability to perform Adaptive query routing based on GTID tracking : instead of proxysql tracking the last GTID by the client, the client has to submit the GTID.

[kirs]

That's correct!

Maybe this diagram would help to illustrate what I'm looking for (it assumes HA-based ProxySQL setup and lots of web app workers):

[renecannao]

The last step here is documenting this feature.
Assigning it to @Val214
Thanks

[renecannao]

Closing this issue because of PR #2469 .
Thank you @kirs