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
{
    Blocks splitted_blocks = splitBlock(block);
    const size_t num_shards = splitted_blocks.size();
    for (size_t shard_idx = 0; shard_idx < num_shards; ++shard_idx)
        if (splitted_blocks[shard_idx].rows())
            writeAsyncImpl(splitted_blocks[shard_idx], shard_idx);
    ++inserted_blocks;
}
void DistributedBlockOutputStream::writeAsyncImpl(const Block & block, size_t shard_id)
{
    const auto & shard_info = cluster->getShardsInfo()[shard_id];
    const auto & settings = context.getSettingsRef();
    if (shard_info.hasInternalReplication())
    {
        if (shard_info.isLocal() && settings.prefer_localhost_replica)
            
            writeToLocal(block, shard_info.getLocalNodeCount());
        else
        {
            const auto & path = shard_info.insertPathForInternalReplication(
                settings.prefer_localhost_replica,
                settings.use_compact_format_in_distributed_parts_names);
            if (path.empty())
                throw Exception("Directory name for async inserts is empty", ErrorCodes::LOGICAL_ERROR);
            writeToShard(block, {path});
        }
    }
    else
    {
        if (shard_info.isLocal() && settings.prefer_localhost_replica)