**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.
MergeTreeData::DataPartsVector normal_parts;
    for (const auto & part : parts)
    {
        const auto & projections = part->getProjectionParts();
        auto it = projections.find(candidate.desc->name);
        if (it != projections.end())
            projection_parts.push_back(it->second);
        else
            normal_parts.push_back(part);
    }
    if (projection_parts.empty())
        return;
    auto projection_result_ptr = reader.estimateNumMarksToRead(
        projection_parts,
        candidate.required_columns,
        metadata_snapshot,
        candidate.desc->metadata,
        query_info,
        query_context,
        settings.max_threads,
        max_added_blocks);
    if (projection_result_ptr->error())
        return;
    auto sum_marks = projection_result_ptr->marks();
    if (normal_parts.empty())
    {
        /
        /
        candidate.complete = true;
    }