Run in-memory aex9 tasks asynchronously

[jyeshe]

The #730 enables the in-memory aex9 balance update.

It's performed synchronously (with parallel tasks) and with a timeout of 1 second per task (that involves a contract dry-run).

Pending cases to be handled having the instantaneous AEX9 sync requirement in mind:

• Process update for contracts with bigger balances (currently discarded and as a reference balances contract dry-run with thousand entries takes more than 1 minute)
• Process multiple calls to same contract only once if already enqueued (dedup tasks)
• Handle many aex9 balance updates avoiding the result of other transactions (like :spend_tx for AE transfer) to be available with a delay. An example of delay lower limit would be 10 seconds for 80+ balance updates taking 1 second each on a machine with 8 threads.

[jyeshe]

• Differentiate on balance endpoints when it is not yet available (pending dry-run) from not existing ones.

[jyeshe]

From #818 notes:

• Keep the sorting while enqueuing with State
• Allow enqueuing tasks to rerun if it's in processing state
• Avoid rerunning the tasks during in-memory sync by detecting invalidations outside of the task
• After 3, cache next hashes in a way to avoid walking through the blocks repeatedly for every task call.

[thepiwo]

I feel this get way less important when we will be moving more towards tracking events, any thoughts @jyeshe

[jyeshe]

I feel this get way less important when we will be moving more towards tracking events, any thoughts @jyeshe

Yes, except for the contract init that is still needed to be async to avoid blocking the txs sync.

[thepiwo]

@jyeshe agree, but usually after init there is not much load on dry-running (except for discussed attack vectors) as init is gas limited, so not high priority

also referencing #969 here

[jyeshe]

@jyeshe agree, but usually after init there is not much load on dry-running (except for discussed attack vectors) as init is gas limited, so not high priority

also referencing #969 here

On AEX-9 the need for the feature continues the same by any mdw solution to balances. I would like to close this as the event based solution will coexist on at least on one release.

[thepiwo]

done except for the events adaptation and the total_pending counter that are covered by #969 and #869

(copy pasted from @jyeshe chat)