Method check

src/MergeTreeCommon/MergeTreeMetaBase.cpp:1405–1547

}

void MergeTreeMetaBase::MergingParams::check(const StorageInMemoryMetadata & metadata, bool attach) const
{
    const bool has_unique_key = metadata.hasUniqueKey();
    const auto columns = metadata.getColumns().getAllPhysical();

    if (!sign_column.empty() && mode != MergingParams::Collapsing && mode != MergingParams::VersionedCollapsing)
        throw Exception("Sign column for MergeTree cannot be specified in modes except Collapsing or VersionedCollapsing.",
                        ErrorCodes::LOGICAL_ERROR);

    if (!has_unique_key && !version_column.empty() && mode != MergingParams::Replacing && mode != MergingParams::VersionedCollapsing)
        throw Exception("Version column for MergeTree cannot be specified in modes except Replacing or VersionedCollapsing.",
                        ErrorCodes::LOGICAL_ERROR);

    if (!columns_to_sum.empty() && mode != MergingParams::Summing)
        throw Exception("List of columns to sum for MergeTree cannot be specified in all modes except Summing.",
                        ErrorCodes::LOGICAL_ERROR);

    /// Check that if the sign column is needed, it exists and is of type Int8.
    auto check_sign_column = [this, & columns](bool is_optional, const std::string & storage)
    {
        if (sign_column.empty())
        {
            if (is_optional)
                return;

            throw Exception("Logical error: Sign column for storage " + storage + " is empty", ErrorCodes::LOGICAL_ERROR);
        }

        bool miss_column = true;
        for (const auto & column : columns)
        {
            if (column.name == sign_column)
            {
                if (!typeid_cast<const DataTypeInt8 *>(column.type.get()))
                    throw Exception("Sign column (" + sign_column + ") for storage " + storage + " must have type Int8."
                            " Provided column of type " + column.type->getName() + ".", ErrorCodes::BAD_TYPE_OF_FIELD);
                miss_column = false;
                break;
            }
        }
        if (miss_column)
            throw Exception("Sign column " + sign_column + " does not exist in table declaration.", ErrorCodes::NO_SUCH_COLUMN_IN_TABLE);
    };

    /// that if the version_column column is needed, it exists and is of unsigned integer type.
    auto check_version_column = [this, & columns](bool is_optional, const std::string & storage)
    {
        if (version_column.empty())
        {
            if (is_optional)
                return;

            throw Exception("Logical error: Version column for storage " + storage + " is empty", ErrorCodes::LOGICAL_ERROR);
        }

        bool miss_column = true;
        for (const auto & column : columns)
        {