**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'
```
{
        writePartLog(
            PartLogElement::MUTATE_PART, execution_status, stopwatch.elapsed(),
            entry.new_part_name, new_part, future_mutated_part.parts, merge_entry.get());
    };
    try
    {
        new_part = merger_mutator.mutatePartToTemporaryPart(
            future_mutated_part, metadata_snapshot, commands, *merge_entry,
            entry.create_time, getContext(), reserved_space, table_lock);
        renameTempPartAndReplace(new_part, nullptr, &transaction);
        try
        {
            checkPartChecksumsAndCommit(transaction, new_part);
        }
        catch (const Exception & e)
        {
            if (MergeTreeDataPartChecksums::isBadChecksumsErrorCode(e.code()))
            {
                transaction.rollback();
                ProfileEvents::increment(ProfileEvents::DataAfterMutationDiffersFromReplica);
                LOG_ERROR(log, "{}. Data after mutation is not byte-identical to data on another replicas. We will download merged part from replica to force byte-identical result.", getCurrentExceptionMessage(false));
                write_part_log(ExecutionStatus::fromCurrentException());
                tryRemovePartImmediately(std::move(new_part));
                
                
                return false;
            }
            throw;
        }