Hello,

after updating clickhouse from 21.2.3.15-2 to 21.3.2.5-2 I see those warnings :

 `<Warning> default.osb4_reverse.DirectoryMonitor: Structure does not match (remote: Path LowCardinality(String) ColumnLowCardinality(size = 0, UInt8(size = 0), ColumnUnique(size = 1, String(size = 1))), Value Float64 Float64(size = 0), Time UInt32 UInt32(size = 0), Date Date UInt16(size = 0), Timestamp UInt32 UInt32(size = 0), local: Path LowCardinality(String) ColumnLowCardinality(size = 0, UInt16(size = 0), ColumnUnique(size = 1, String(size = 1))), Value Float64 Float64(size = 0), Time UInt32 UInt32(size = 0), Date Date UInt16(size = 0), Timestamp UInt32 UInt32(size = 0)), implicit conversion will be done`

I think this is related to https://github.com/ClickHouse/ClickHouse/pull/19947

The only difference between remote and local I found inside this log is :

ColumnLowCardinality(size = 0, UInt8(size = 0) to
ColumnLowCardinality(size = 0, UInt16(size = 0)

But I don't see the difference between the tables.

```
SHOW CREATE TABLE default.osb4_reverse

CREATE TABLE default.osb4_reverse
(
    `Path` LowCardinality(String) CODEC(ZSTD(15)),
    `Value` Float64 CODEC(Gorilla, ZSTD(22)),
    `Time` UInt32 CODEC(DoubleDelta, ZSTD(15)),
    `Date` Date CODEC(Delta(2), ZSTD(22)),
    `Timestamp` UInt32 CODEC(ZSTD(15))
)
ENGINE = Distributed('osb4_hpc_metrics', '', 'osb4_reverse', rand())


CREATE TABLE osb4_metrics_r0.osb4_reverse
(
    `Path` LowCardinality(String) CODEC(ZSTD(15)),
    `Value` Float64 CODEC(Gorilla, ZSTD(22)),
    `Time` UInt32 CODEC(DoubleDelta, ZSTD(15)),
    `Date` Date CODEC(Delta(2), ZSTD(22)),
    `Timestamp` UInt32 CODEC(ZSTD(15))
)
ENGINE = ReplicatedReplacingMergeTree('/clickhouse/clusters/osb4_hpc_metrics/tables/{table4}/data', '{host2}')
PARTITION BY toYYYYMM(Date)
ORDER BY (Path, Time)
TTL Date + toIntervalMonth(6)
SETTINGS index_granularity = 8192
```

Any hints ?

Ralph
initWritingJobs(block, start, end);
        pool.emplace(remote_jobs_count + local_jobs_count);
        if (!throttler && (settings.max_network_bandwidth || settings.max_network_bytes))
        {
            throttler = std::make_shared<Throttler>(settings.max_network_bandwidth, settings.max_network_bytes,
                                                    "Network bandwidth limit for a query exceeded.");
        }
        watch.restart();
    }
    watch_current_block.restart();
    if (num_shards > 1)
    {
        auto current_selector = createSelector(block);
        
        for (size_t shard_index : ext::range(0, num_shards))
            per_shard_jobs[shard_index].shard_current_block_permutation.resize(0);
        for (size_t i = 0; i < block.rows(); ++i)
            per_shard_jobs[current_selector[i]].shard_current_block_permutation.push_back(i);
    }
    try
    {
        
        finished_jobs_count = 0;
        for (size_t shard_index : ext::range(0, shards_info.size()))
            for (JobReplica & job : per_shard_jobs[shard_index].replicas_jobs)
                pool->scheduleOrThrowOnError(runWritingJob(job, block, num_shards));
    }
    catch (...)
    {