You can change the vCPUs or memory of a DB instance as required. If the status of a DB instance changes from Changing instance specifications to Available, the change is successful.
Changing the instance specifications takes 5–15 minutes. During this period, the status of the instance on the Instances page is Changing instance specifications. After a few minutes, you can click the instance name to view the new instance specifications on the displayed Basic Information page.
After the specifications of DB instances 8.0 are changed, the system will change the values of the following parameters accordingly: innodb_buffer_pool_size, innodb_log_buffer_size, max_connections, innodb_buffer_pool_instances, innodb_page_cleaners, innodb_parallel_read_threads, innodb_read_io_threads, innodb_write_io_threads, threadpool_size and query_cache_size.