**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'
```
|| MergeTreePartInfo::contains(part_on_replica, largest_part_found, format_version))
                {
                    largest_part_found = part_on_replica;
                }
            }
        }
        if (!largest_part_found.empty())
        {
            bool the_same_part = largest_part_found == entry.new_part_name;
            
            if (!the_same_part)
            {
                String reject_reason;
                if (!queue.addFuturePartIfNotCoveredByThem(largest_part_found, entry, reject_reason))
                {
                    LOG_INFO(log, "Will not fetch part {} covering {}. {}", largest_part_found, entry.new_part_name, reject_reason);
                    return {};
                }
            }
            return replica;
        }
    }
    return {};
}
String StorageReplicatedMergeTree::findReplicaHavingCoveringPart(
    const String & part_name, bool active, String & found_part_name)
{
    auto zookeeper = getZooKeeper();
    Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");