Thankfully "partial merge join" is disabled by default.

```
milovidov-desktop :) SET max_block_size = 6, join_algorithm = 'partial_merge'

SET max_block_size = 6, join_algorithm = 'partial_merge'

Query id: 600704b7-b455-4726-8a9c-8e45b509f2fb

Ok.

0 rows in set. Elapsed: 0.002 sec. 

milovidov-desktop :) SELECT blockSize() bs FROM (SELECT 1 s) js1 ALL RIGHT JOIN (SELECT arrayJoin([2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3]) s) js2 USING (s) GROUP BY bs ORDER BY bs;

SELECT blockSize() AS bs
FROM
(
    SELECT 1 AS s
) AS js1
ALL RIGHT JOIN
(
    SELECT arrayJoin([2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3]) AS s
) AS js2 USING (s)
GROUP BY bs
ORDER BY bs ASC

Query id: ae51c589-4b69-4e90-a3a9-7ef4ead72af9

→ Progress: 2.00 rows, 2.00 B (18.21 rows/s., 18.21 B/s.)
```

Found by stress test.
{
    std::unique_lock lock(rwlock);
    auto callback = [&](const Block & block)
    {
        if (skip_not_intersected)
            min_max_right_blocks.emplace_back(extractMinMax(block, right_table_keys));
        right_blocks.countBlockSize(block);
    };
    flushed_right_blocks = disk_writer->finishMerge(callback);
    disk_writer.reset();
    
    UInt64 memory_limit = size_limits.max_bytes;
    UInt64 rows_limit = size_limits.max_rows;
    if (!memory_limit && rows_limit)
        memory_limit = right_blocks.bytes * rows_limit / right_blocks.row_count;
    cached_right_blocks = std::make_unique<Cache>(memory_limit);
}
bool MergeJoin::saveRightBlock(Block && block)