Best Data Type for Storing AWS ARNs in MySQL?

Question

What's the best datatype to store an ARN in MySQL? I'm guessing a VARCHAR with a large character limit would be best. Is there a limit to how long ARNs can be? How long of a VARCHAR should I have?

Answer 1

I have found no documentation on the maximum length of an ARN, overall, but it's service-specific, more often than not, with maximum lengths of each element in the ARN -- presumably -- combining within each service to define the maximum as this forum answer suggests.

A quick search indicates that you'll see a maximum of 2048 here or 256 here or the oddly-sized non-power-of-2 111 here or... You get the idea. It varies by service.

The longest ARN I have encountered has been from S3, where an ARN can include a key prefix, so those could theoretically exceed 1,024 though I've not encountered any that actually approached that length.

Bearing in mind that ARNs, or at least many of their elements are case-sensitive, I tend to go with VARBINARY() with a length suited to the expected size range for the service in question. I would expect many applications would be quite comfortable somewhere below 255 but that's an architectural decision specific to your application and the AWS services involved.