**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.
virtual bool unlockSharedData(const IMergeTreeDataPart &) const { return true; }
    
    
    virtual bool tryToFetchIfShared(const IMergeTreeDataPart &, const DiskPtr &, const String &) { return false; }
    
    
    
    DataParts currently_submerging_big_parts;
    std::map<String, EmergingPartInfo> currently_emerging_big_parts;
    
    mutable std::mutex currently_submerging_emerging_mutex;
protected:
    friend class IMergeTreeDataPart;
    friend class MergeTreeDataMergerMutator;
    friend struct ReplicatedMergeTreeTableMetadata;
    friend class StorageReplicatedMergeTree;
    friend class MergeTreeDataWriter;
    friend class MergeTask;
    bool require_part_metadata;
    
    
    String relative_data_path;
    
    ColumnSizeByName column_sizes;
    
    IndexSizeByName secondary_index_sizes;