**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'
```
#include <DataStreams/RemoteBlockInputStream.h>
#include <DataStreams/copyData.h>
#include <Poco/DirectoryIterator.h>
#include <common/range.h>
#include <common/scope_guard.h>
#include <common/scope_guard_safe.h>
#include <algorithm>
#include <ctime>
#include <filesystem>
#include <iterator>
#include <numeric>
#include <thread>
#include <future>
#include <boost/algorithm/string/join.hpp>
namespace fs = std::filesystem;
namespace ProfileEvents
{
    extern const Event ReplicatedPartMerges;
    extern const Event ReplicatedPartMutations;
    extern const Event ReplicatedPartFailedFetches;
    extern const Event ReplicatedPartFetchesOfMerged;
    extern const Event ObsoleteReplicatedParts;
    extern const Event ReplicatedPartFetches;
    extern const Event DataAfterMergeDiffersFromReplica;
    extern const Event DataAfterMutationDiffersFromReplica;
    extern const Event CreatedLogEntryForMerge;
    extern const Event NotCreatedLogEntryForMerge;
    extern const Event CreatedLogEntryForMutation;
    extern const Event NotCreatedLogEntryForMutation;
}