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
auto connection = pool->get(timeouts, &header.insert_settings);
        RemoteBlockOutputStream remote{*connection, timeouts,
            header.insert_query, header.insert_settings, header.client_info};
        remote.writePrefix();
        writeRemoteConvert(header, remote, in, log);
        remote.writeSuffix();
    }
    catch (const Exception & e)
    {
        maybeMarkAsBroken(file_path, e);
        throw;
    }
    auto dir_sync_guard = getDirectorySyncGuard(dir_fsync, disk, relative_path);
    markAsSend(file_path);
    LOG_TRACE(log, "Finished processing `{}`", file_path);
}
struct StorageDistributedDirectoryMonitor::BatchHeader
{
    Settings settings;
    String query;
    ClientInfo client_info;
    String sample_block_structure;
    BatchHeader(Settings settings_, String query_, ClientInfo client_info_, String sample_block_structure_)
        : settings(std::move(settings_))
        , query(std::move(query_))
        , client_info(std::move(client_info_))
        , sample_block_structure(std::move(sample_block_structure_))
    {
    }
    bool operator==(const BatchHeader & other) const