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.
, is_right(isRight(table_join->kind()))
    , is_full(isFull(table_join->kind()))
    , max_joined_block_rows(table_join->maxJoinedBlockRows())
    , max_rows_in_right_block(table_join->maxRowsInRightBlock())
    , max_files_to_merge(table_join->maxFilesToMerge())
{
    switch (table_join->strictness())
    {
        case ASTTableJoin::Strictness::All:
            break;
        case ASTTableJoin::Strictness::Any:
        case ASTTableJoin::Strictness::Semi:
            if (!is_left && !is_inner)
                throw Exception("Not supported. MergeJoin supports SEMI and ANY variants only for LEFT and INNER JOINs.",
                                ErrorCodes::NOT_IMPLEMENTED);
            break;
        default:
            throw Exception("Not supported. MergeJoin supports ALL, ANY and SEMI JOINs variants.", ErrorCodes::NOT_IMPLEMENTED);
    }
    if (!max_rows_in_right_block)
        throw Exception("partial_merge_join_rows_in_right_blocks cannot be zero", ErrorCodes::PARAMETER_OUT_OF_BOUND);
    if (max_files_to_merge < 2)
        throw Exception("max_files_to_merge cannot be less than 2", ErrorCodes::PARAMETER_OUT_OF_BOUND);
    if (!size_limits.hasLimits())
    {
        size_limits.max_bytes = table_join->defaultMaxBytes();
        if (!size_limits.max_bytes)
            throw Exception("No limit for MergeJoin (max_rows_in_join, max_bytes_in_join or default_max_bytes_in_join have to be set)",
                            ErrorCodes::PARAMETER_OUT_OF_BOUND);
    }