**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.
for (auto && part : write_ahead_log->restore(metadata_snapshot, getContext()))
                        disk_wal_parts.push_back(std::move(part));
                }
                else if (settings->in_memory_parts_enable_wal)
                {
                    MergeTreeWriteAheadLog wal(*this, disk_ptr, it->name());
                    for (auto && part : wal.restore(metadata_snapshot, getContext()))
                        disk_wal_parts.push_back(std::move(part));
                }
            }
        });
    }
    pool.wait();
    for (auto & [_, disk_wal_parts] : disk_wal_part_map)
        parts_from_wal.insert(
            parts_from_wal.end(), std::make_move_iterator(disk_wal_parts.begin()), std::make_move_iterator(disk_wal_parts.end()));
    size_t num_parts = 0;
    std::queue<std::vector<std::pair<String, DiskPtr>>> parts_queue;
    for (auto & [_, disk_parts] : disk_part_map)
    {
        if (disk_parts.empty())
            continue;
        num_parts += disk_parts.size();
        parts_queue.push(std::move(disk_parts));
    }
    auto part_lock = lockParts();
    data_parts_indexes.clear();
    if (num_parts == 0 && parts_from_wal.empty())
    {
        LOG_DEBUG(log, "There are no data parts");