**Use case**

Currently, `system.replicas` table has `total_replicas` and `active_replicas` columns which are useful to check/alert when some replicas are down. One problem, these columns are numbers. They tell when there is a problem, but you need to further check ZooKeeper or query all the nodes to detect what exact replicas (hosts) are down/inactive/have problems.

**Describe the solution you'd like**

Add a replicas column maybe as a map which would contain the replica name, and it's status. Or, add 2 array columns with `replica_names` and `active_replica_names`

**Alternative**

Something along the line

```sql
select path, value from system.zookeeper where path IN (
    select concat(path, '/', name) from system.zookeeper where path in (select concat(zookeeper_path, '/replicas') from system.replicas)
)
and name = 'is_active'
```
break;
        }
        else if (rc == Coordination::Error::ZBADVERSION)
        {
            
            if (query_context->getZooKeeperMetadataTransaction())
                throw Exception("Cannot execute alter, because mutations version was suddenly changed due to concurrent alter",
                                ErrorCodes::CANNOT_ASSIGN_ALTER);
            LOG_TRACE(log, "Version conflict when trying to create a mutation node, retrying...");
            continue;
        }
        else
            throw Coordination::Exception("Unable to create a mutation znode", rc);
    }
    waitMutation(mutation_entry.znode_name, query_context->getSettingsRef().mutations_sync);
}
void StorageReplicatedMergeTree::waitMutation(const String & znode_name, size_t mutations_sync) const
{
    if (!mutations_sync)
        return;
    
    auto zookeeper = getZooKeeper();
    Strings replicas;
    if (mutations_sync == 2) 
        replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
    else if (mutations_sync == 1) 
        replicas.push_back(replica_name);
    waitMutationToFinishOnReplicas(replicas, znode_name);
}
std::vector<MergeTreeMutationStatus> StorageReplicatedMergeTree::getMutationsStatus() const