**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.
{
            /
            std::shuffle(candidates.begin(), candidates.end(), thread_local_rng);
            String selected_disk_name = candidates.front();
            WriteBufferFromOwnString log_str;
            writeCString("\nbalancer: \n", log_str);
            for (const auto & [disk_name, per_disk_parts] : disk_parts_for_logging)
                writeString(fmt::format("  {}: [{}]\n", disk_name, fmt::join(per_disk_parts, ", ")), log_str);
            LOG_DEBUG(log, log_str.str());
            if (ttl_infos)
                reserved_space = tryReserveSpacePreferringTTLRules(
                    metadata_snapshot,
                    part_size,
                    *ttl_infos,
                    time(nullptr),
                    max_volume_index,
                    is_insert,
                    getStoragePolicy()->getDiskByName(selected_disk_name));
            else
                reserved_space = tryReserveSpace(part_size, getStoragePolicy()->getDiskByName(selected_disk_name));
            if (reserved_space)
            {
                currently_emerging_big_parts.emplace(
                    part_name, EmergingPartInfo{reserved_space->getDisk(0)->getName(), part_info.partition_id, part_size});
                for (const auto & part : covered_parts)
                {
                    if (currently_submerging_big_parts.count(part))
                        LOG_WARNING(log, "currently_submerging_big_parts contains duplicates. JBOD might lose balance");
                    else
                        currently_submerging_big_parts.insert(part);