Aurora DB 中的 Alter 命令（添加新列）

Question

There is a requirement to add a new column with a default value varchar(1) where the table has 75 million+ records. Performed the tests in perf environment, it ran fine with 40 mins, but there is no live traffic. Is there anyway we can expedite this? Can disabling the indexes on the table may help expedite the alter command?

Answer 1

Disabling the indexes might help, but when you enable the indexes again, they'll have to be rebuilt, which will also take a long time. I don't think you'll save any time in the end.

But I would recommend learning to use pt-online-schema-change . This is a tool that runs schema changes in the background, so to speak, while your application can continue to read and write the original table.

It will probably take longer to run the alter. But you don't mind, because there is no downtime. Say it takes two hours instead of 40 minutes. It's okay because the application doesn't have to wait for the schema change to finish.

At my job, we run hundreds of schema changes per week in production, without downtime. The schema change tool does need to lock the table briefly at the start and at the end of its work.