**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 &,
    const StorageMetadataPtr &,
    const ASTPtr & partition,
    bool final,
    bool deduplicate,
    const Names & deduplicate_by_columns,
    ContextPtr query_context)
{
    
    
    auto table_lock = lockForShare(query_context->getCurrentQueryId(), query_context->getSettingsRef().lock_acquire_timeout);
    assertNotReadonly();
    if (!is_leader)
        throw Exception("OPTIMIZE cannot be done on this replica because it is not a leader", ErrorCodes::NOT_A_LEADER);
    constexpr size_t max_retries = 10;
    std::vector<ReplicatedMergeTreeLogEntryData> merge_entries;
    {
        auto zookeeper = getZooKeeper();
        auto handle_noop = [&] (const String & message)
        {
            if (query_context->getSettingsRef().optimize_throw_if_noop)
                throw Exception(message, ErrorCodes::CANNOT_ASSIGN_OPTIMIZE);
            return false;
        };
        const auto storage_settings_ptr = getSettings();
        auto metadata_snapshot = getInMemoryMetadataPtr();
        if (!partition && final)
        {
            DataPartsVector data_parts = getDataPartsVector();