I don’t think that the changes will be made available for OH2 (THINK!)
On the actual topics you have read:
The performance issue that is worked on was observed on the updated version after an change on the updated version. IOW for the rrd4j version in OH2 there is no reported perfomance issue. The problem on the new version is related to items with a dimension, the old version does NOT support that all. Additionally the performance issue was only observed on a device with “constrained resources”.
If you do observe performance issue I’d wouldsuggedt to file an issue. Even if that one will not be worked on (ATM?), maintainers would be notified.
Personally I would not be surprised to see performence issues ona private system persisting more the 1000 items (any service!)!
@jwiseman Sorry, no chance. As @opus correctly says, the performance issues that were just fixed were introduced by a recent change, so the result is not any faster than what you have on 2.x.
Also note that 2.x actually does not have any persistence services, but all of them are coming from 1.x and being used through the compatibility-layer - and the 1.x repo is fully out of maintenance. Therefore if any improvements are done, those will only happen on 3.x.