Method joinBlock

src/Interpreters/MergeJoin.cpp:644–702

}

void MergeJoin::joinBlock(Block & block, ExtraBlockPtr & not_processed)
{
    Names lowcard_keys = lowcard_right_keys;
    if (block)
    {
        JoinCommon::checkTypesOfKeys(block, table_join->keyNamesLeft(), right_table_keys, table_join->keyNamesRight());
        materializeBlockInplace(block);

        for (const auto & column_name : table_join->keyNamesLeft())
        {
            if (block.getByName(column_name).type->lowCardinality())
                lowcard_keys.push_back(column_name);
        }

        JoinCommon::removeLowCardinalityInplace(block, table_join->keyNamesLeft(), false);

        sortBlock(block, left_sort_description);

        if (nullable_left_side)
            JoinCommon::convertColumnsToNullable(block);
    }

    if (!not_processed && left_blocks_buffer)
    {
        if (!block || block.rows())
            block = left_blocks_buffer->exchange(std::move(block));
        if (!block)
            return;
    }

    if (is_in_memory)
    {
        if (is_all_join)
            joinSortedBlock<true, true>(block, not_processed);
        else
            joinSortedBlock<true, false>(block, not_processed);
    }
    else
    {
        if (is_all_join)
            joinSortedBlock<false, true>(block, not_processed);
        else
            joinSortedBlock<false, false>(block, not_processed);
    }

    /// Back thread even with no data. We have some unfinished data in buffer.
    if (!not_processed && left_blocks_buffer)
        not_processed = std::make_shared<NotProcessed>(NotProcessed{{}, 0, 0, 0});

    for (const auto & column_name : lowcard_keys)
    {
        if (!block.has(column_name))
            continue;
        if (auto & col = block.getByName(column_name); !col.type->lowCardinality())
            JoinCommon::changeLowCardinalityInplace(col);
    }

    JoinCommon::restoreLowCardinalityInplace(block);