**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'
```
const ASTPtr & partition,
    const StorageMetadataPtr & metadata_snapshot,
    const String & from_,
    bool fetch_part,
    ContextPtr query_context)
{
    Macros::MacroExpansionInfo info;
    info.expand_special_macros_only = false; 
    info.table_id = getStorageID();
    info.table_id.uuid = UUIDHelpers::Nil;
    auto expand_from = query_context->getMacros()->expand(from_, info);
    String auxiliary_zookeeper_name = extractZooKeeperName(expand_from);