**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'
```
String found_new_part_name;
        
        DataPartPtr src_table_part;
        
        String replica;
    };
    using PartDescriptionPtr = std::shared_ptr<PartDescription>;
    using PartDescriptions = std::vector<PartDescriptionPtr>;
    PartDescriptions all_parts;
    PartDescriptions parts_to_add;
    DataPartsVector parts_to_remove;
    auto table_lock_holder_dst_table = lockForShare(
            RWLockImpl::NO_QUERY, getSettings()->lock_acquire_timeout_for_background_operations);
    auto dst_metadata_snapshot = getInMemoryMetadataPtr();
    for (size_t i = 0; i < entry_replace.new_part_names.size(); ++i)
    {
        all_parts.emplace_back(std::make_shared<PartDescription>(i,
            entry_replace.src_part_names.at(i),
            entry_replace.new_part_names.at(i),
            entry_replace.part_names_checksums.at(i),
            format_version));
    }
    
    {
        auto data_parts_lock = lockParts();
        for (const PartDescriptionPtr & part_desc : all_parts)
        {
            if (!getActiveContainingPart(part_desc->new_part_info, MergeTreeDataPartState::Committed, data_parts_lock))
                parts_to_add.emplace_back(part_desc);
        }