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

[Vladislav Shpilevoy]

Hi! Thanks for the review!

On 10.06.2021 17:02, Cyrill Gorcunov wrote:
> 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.

This would work, technically. But TBH I don't see how it is simpler.

>>  		if (cmp == 0 && tt_uuid_compare(&replica->uuid,
>>  						&leader->uuid) > 0)
>>  			continue;
>> +	elect:
> 
> seems extra tab here?

Yes, fixed on the branch.