cloud: database 'processing' when add attributes

When I'm adding attributes to a collection, I get 'processing' message. What does this mean, and how long it will take to process? Thank you

TL;DR

The user is asking about the meaning of the 'processing' message they receive when adding attributes to a collection in a SQL database on the cloud. The response explains that the 'processing' message indicates that the database is in progress of updating the schema and shifting every row on the disk to make space for new data. It is mentioned that updating attributes in an existing database is typically slow. There is no solution provided in the support thread, only an explanation of the 'processing' message.