**How to reproduce**
Clickhouse server 20.13.1.5273
```
CREATE TABLE default.test
(
`key` UInt32,
`ts` DateTime CODEC(DoubleDelta, LZ4),
`db_time` DateTime DEFAULT now() COMMENT 'spout-ignore' CODEC(DoubleDelta, LZ4)
)
ENGINE = MergeTree
PARTITION BY toStartOfTenMinutes(db_time)
ORDER BY (key, ts)
TTL db_time + toIntervalHour(3)
SETTINGS index_granularity = 8192, merge_with_ttl_timeout = 3600, min_rows_for_compact_part = 1000000, min_bytes_for_compact_part = 200000000, in_memory_parts_enable_wal = 0;


INSERT INTO test(key, ts) SELECT number % 1000, now() + intDiv(number,1000) FROM numbers(500);

SELECT * FROM test;
500 rows in set. Elapsed: 0.003 sec.

DETACH TABLE test;

ATTACH TABLE test;

SELECT * FROM test;

0 rows in set. Elapsed: 0.002 sec.
```

**Expected behavior**
Clickhouse would flush parts on disk.
{
    const auto & partition_ast = ast->as<ASTPartition &>();
    if (!partition_ast.value)
    {
        MergeTreePartInfo::validatePartitionID(partition_ast.id, format_version);
        return partition_ast.id;
    }
    if (format_version < MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
    {
        /
        const auto * partition_lit = partition_ast.value->as<ASTLiteral>();
        if (partition_lit && partition_lit->value.getType() == Field::Types::String)
        {
            String partition_id = partition_lit->value.get<String>();
            MergeTreePartInfo::validatePartitionID(partition_id, format_version);
            return partition_id;
        }
    }
    /
    auto metadata_snapshot = getInMemoryMetadataPtr();
    const Block & key_sample_block = metadata_snapshot->getPartitionKey().sample_block;
    size_t fields_count = key_sample_block.columns();
    if (partition_ast.fields_count != fields_count)