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'。
ContextPtr local_context,
    QueryProcessingStage::Enum to_stage,
    const StorageMetadataPtr &,
    SelectQueryInfo & query_info) const
{
    if (destination_id)
    {
        auto destination = DatabaseCatalog::instance().getTable(destination_id, local_context);
        if (destination.get() == this)
            throw Exception("Destination table is myself. Read will cause infinite loop.", ErrorCodes::INFINITE_LOOP);
        return destination->getQueryProcessingStage(local_context, to_stage, destination->getInMemoryMetadataPtr(), query_info);
    }
    return QueryProcessingStage::FetchColumns;
}
Pipe StorageBuffer::read(
    const Names & column_names,
    const StorageMetadataPtr & metadata_snapshot,
    SelectQueryInfo & query_info,
    ContextPtr local_context,
    QueryProcessingStage::Enum processed_stage,
    const size_t max_block_size,
    const unsigned num_streams)
{
    QueryPlan plan;
    read(plan, column_names, metadata_snapshot, query_info, local_context, processed_stage, max_block_size, num_streams);
    return plan.convertToPipe(
        QueryPlanOptimizationSettings::fromContext(local_context),
        BuildQueryPipelineSettings::fromContext(local_context));
}
void StorageBuffer::read(