**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'
```
if (zookeeper->exists(zookeeper_path + "/dropped"))
        {
            
            
            
            LOG_WARNING(log, "Removing leftovers from table {} (this might take several minutes)", zookeeper_path);
            String drop_lock_path = zookeeper_path + "/dropped/lock";
            Coordination::Error code = zookeeper->tryCreate(drop_lock_path, "", zkutil::CreateMode::Ephemeral);
            if (code == Coordination::Error::ZNONODE || code == Coordination::Error::ZNODEEXISTS)
            {
                LOG_WARNING(log, "The leftovers from table {} were removed by another replica", zookeeper_path);
            }
            else if (code != Coordination::Error::ZOK)
            {
                throw Coordination::Exception(code, drop_lock_path);
            }
            else
            {
                auto metadata_drop_lock = zkutil::EphemeralNodeHolder::existing(drop_lock_path, *zookeeper);
                if (!removeTableNodesFromZooKeeper(zookeeper, zookeeper_path, metadata_drop_lock, log))
                {
                    
                    continue;
                }
            }
        }
        LOG_DEBUG(log, "Creating table {}", zookeeper_path);
        
        String metadata_str = ReplicatedMergeTreeTableMetadata(*this, metadata_snapshot).toString();