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'。
{
    auto table_id = getStorageID();
    checkAlterIsPossible(params, local_context);
    auto metadata_snapshot = getInMemoryMetadataPtr();
    
    
    
    optimize({} , metadata_snapshot, {} , false , false , {}, local_context);
    StorageInMemoryMetadata new_metadata = *metadata_snapshot;
    params.apply(new_metadata, local_context);
    DatabaseCatalog::instance().getDatabase(table_id.database_name)->alterTable(local_context, table_id, new_metadata);
    setInMemoryMetadata(new_metadata);
}
void registerStorageBuffer(StorageFactory & factory)
{
    /** Buffer(db, table, num_buckets, min_time, max_time, min_rows, max_rows, min_bytes, max_bytes)
      *
      * db, table - in which table to put data from buffer.
      * num_buckets - level of parallelism.
      * min_time, max_time, min_rows, max_rows, min_bytes, max_bytes - conditions for flushing the buffer,
      * flush_time, flush_rows, flush_bytes - conditions for flushing.
      */
    factory.registerStorage("Buffer", [](const StorageFactory::Arguments & args)
    {
        ASTs & engine_args = args.engine_args;
        if (engine_args.size() < 9 || engine_args.size() > 12)
            throw Exception("Storage Buffer requires from 9 to 12 parameters: "
                " destination_database, destination_table, num_buckets, min_time, max_time, min_rows, max_rows, min_bytes, max_bytes[, flush_time, flush_rows, flush_bytes].",