**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.
bool supportsFinal() const override
    {
        return merging_params.mode == MergingParams::Collapsing
            || merging_params.mode == MergingParams::Summing
            || merging_params.mode == MergingParams::Aggregating
            || merging_params.mode == MergingParams::Replacing
            || merging_params.mode == MergingParams::Graphite
            || merging_params.mode == MergingParams::VersionedCollapsing;
    }
    bool supportsSubcolumns() const override { return true; }
    NamesAndTypesList getVirtuals() const override;
    bool mayBenefitFromIndexForIn(const ASTPtr & left_in_operand, ContextPtr, const StorageMetadataPtr & metadata_snapshot) const override;
    
    void loadDataParts(bool skip_sanity_checks);
    String getLogName() const { return log_name; }
    Int64 getMaxBlockNumber() const;
    
    DataParts getDataParts(const DataPartStates & affordable_states) const;