[tyingq]

> accumulate locally

Is that an option in AppEngine? The memcache docs seem to indicate the free tier has undocumented eviction policies.

[showdeddd]

You have to implement that with your own code but it isn't much more than a dict/map and a timestamp for last update.

[tyingq]

Same-ish problem, though. You wouldn't know for sure the instance will run again...your dict/map data can be dropped. I don't see any sort of instance timeout callback where you could guard against that.

[showdeddd]

I think it's negligible. The only metrics you lose are on rare scaledowns and they are averaged out anyways. GCP likes to keep instances idle for a long time.