[Tarantool-patches] [PATCH 5/6] replication: use 'score' to find a join-master

[Cyrill Gorcunov]

On Sat, Jun 05, 2021 at 01:37:59AM +0200, Vladislav Shpilevoy wrote:
> +		int score = 0;
>  		/*
> -		 * Try to find a replica which has already left
> -		 * orphan mode.
> +		 * Prefer instances not configured as read-only via box.cfg, and
> +		 * not being in read-only state due to any other reason. The
> +		 * config is stronger because if it is configured as read-only,
> +		 * it is in read-only state for sure, until the config is
> +		 * changed.
>  		 */
> -		if (ballot->is_ro && !leader_ballot->is_ro)
> +		if (!ballot->is_ro_cfg)
> +			score += 5;
> +		if (!ballot->is_ro)
> +			score += 1;
> +		if (leader_score < score)
> +			goto elect;
> +		if (score < leader_score)
>  			continue;

Vlad, if only I'm not missing something obvious we can do simplier
without branching at all, say

		score = (ballot->is_booted << 3) |
			(ballot->is_ro_cfg << 2) |
			(ballot->is_ro << 1);

up to you, just an idea.
...
>  		if (cmp == 0 && tt_uuid_compare(&replica->uuid,
>  						&leader->uuid) > 0)
>  			continue;
> +	elect:

seems extra tab here?

>  		leader = replica;
> +		leader_score = score;
>  	}
>  	return leader;
>  }