Change the table comment after created the table is not supported now?
Like mysql : ALTER TABLE [tableName] COMMNET [comment]; 
The sql "ALTER TABLE `system`.tables UPDATE Comment='test' WHERE NAME='t1';" also not supported!!!
My version is '21.9.4.35'。
: SourceWithProgress(
            metadata_snapshot->getSampleBlockForColumns(column_names_, storage.getVirtuals(), storage.getStorageID()))
        , column_names_and_types(metadata_snapshot->getColumns().getByNames(ColumnsDescription::All, column_names_, true))
        , buffer(buffer_) {}
    String getName() const override { return "Buffer"; }
protected:
    Chunk generate() override
    {
        Chunk res;
        if (has_been_read)
            return res;
        has_been_read = true;
        std::unique_lock lock(buffer.lockForReading());
        if (!buffer.data.rows())
            return res;
        Columns columns;
        columns.reserve(column_names_and_types.size());
        for (const auto & elem : column_names_and_types)
            columns.emplace_back(getColumnFromBlock(buffer.data, elem));
        UInt64 size = columns.at(0)->size();
        res.setColumns(std::move(columns), size);
        return res;
    }
private:
    NamesAndTypesList column_names_and_types;
    StorageBuffer::Buffer & buffer;
    bool has_been_read = false;
};
QueryProcessingStage::Enum StorageBuffer::getQueryProcessingStage(