CPS-2000 Schema object cache not distributed.

References

CPS-2000 - Getting issue details... STATUS

Issues & Decisions

Solution Proposal

Assumption

1. during Upgrade two CM Handle LCM notifications are sent: 1) READY→LOCKED (for upgrade). 2) LOCKED → READY
2. LCM events should be processed within Milliseconds

Alternative 0: Remove existing cache

• tried but mush slower and ODL memory leak experienced

Alternative 1: New CPS-Core Kafka Message without confirmation

Notes

1. LCM event should; be processed within milliseconds
2. CPS-Core needs (new) infrastructure to produce (and Consume) Kafka Cloud Events
3. Caffeine cache has an expiry (10mins) So NOT all models are cached all the time
4. Worst case scenario: an update (with newly modelled data) happens before cache expiry. Update gets reject (fails validation)
   1. mitigation: Invalidate cache upon validation error and try again (consider this as an extension alternative 2 )
5. Delete-use case need to clear cache (for all instances) as well

Alternative 2: Clear Cache upon validation error

1. Worst case scenario: an update (with newly modelled data) happens before cache expiry. Update gets reject (fails validation)
   1. mitigation: Invalidate cache upon validation error and try again (consider this as an extension alternative 2 )

Alternative 3: (existing) Kafka Message with (new) Kafka Confirmation

Not viable without knowing how many instances need to form ie need Hazelcast Cache

Alternative 4: (existing) Kafka Message with (new) Hazelcast Cache (semaphore)

Confirmation

Alternative 5: (existing) Polling (status watchdog) with (new) confirmation

Not viable because upgrades can be completed well withing polling time

Alternative 6: Add version info the cache-key