Keeper: Execute Steward operation immediately on epoch transition

[aoikurokawa]

Problem

• We have to get RebalanceDirected instructions through as fast as possible at the start of an epoch

Solution

• After executing every operation, the keeper check epoch info
• If epoch transitioned, execute steward instructions (RebalanceDirected) immediately.

Flow changes

1. Check epoch schedule, if epoch is transitioned, execute steward instructions
2. Pick operations based on tick and interval
3. Execute operation
4. If executed operation was heavy (send many txs), check epoch info after finishing operation
5. back to 3 until executing all operations
6. back to 1

[gzalz]

The logic here checks out but I do think that we can get even more aggressive with the timing. In this setup we will prioritize the directed rebalance next in the queue. The tasks in the queue can be quite heavy and there's potential for a non-trivial amount of time to pass before rebalance directed is removed from the queue.

Curious to hear thoughts from others on maybe using something like the slot stream from a geyser RPC plugin on a separate task? Or is that overkill? @ebatsell @CoachChuckFF @mrmizz

[ebatsell]

The conditional here should actually be if the Stake Pool has updated, last_updated_epoch I think this is the field. Since increase/decrease commands are locked until that has completed

[aoikurokawa]

You're right!
https://github.com/solana-program/stake-pool/blob/8f705b3cb1a80e49ef4037a593d10713499ea8d7/program/src/processor.rs#L1549-L1551

[aoikurokawa]

ok, changed the if condition

    /// Check `last_update_epoch` field in Stake Pool
    ///
    /// # Process
    ///
    /// 1. Check the field `last_update_epoch` in StakePool account
    /// 2. If the `last_update_epoch` has updated, trigger steward operation
    /// 3. Otherwise, continue next operation
    pub async fn check_last_update_epoch(
        &mut self,
        client: Arc<RpcClient>,
        last_seen_epoch: &mut Option<u64>,
    ) -> bool {
        if let Some(all_steward_accounts) = self.all_steward_accounts.as_ref() {
            if let Ok(stake_pool) =
                get_stake_pool_account(&client, &all_steward_accounts.stake_pool_address).await
            {
                if let Some(ref mut seen_epoch) = last_seen_epoch {
                    let has_updated = stake_pool.last_update_epoch > *seen_epoch;
                    *seen_epoch = stake_pool.last_update_epoch;
                    return has_updated;
                } else {
                    *last_seen_epoch = Some(stake_pool.last_update_epoch);
                    return false;
                }
            }
        }

        false
    }