Currently long maintences are done at meriadb10. Also future updates and so on. Having a sql resource would prevent sge scripts to run while database is down/broken and schedules them later when database is available again.
On toolserver there were many sge different resources defined. On Labs there will probably be only three db servers, so having one resource for replicated db, one for tools-db and one for postgre should be enough.
This resource should set to 0 while maintenance is done or replication is broken. This could be done manually or by a load sensor script.
For this the resource must be a simple indicator and does not need to be consumable. On toolserver the resource was consumable to limit the number of queries run at the same time to prevent heavy peak usage. I don't know if this is needed on labs, too.