AWS RDS cold starts

After restoring an AWS RDS database from a snapshot, RDS only lazy loads data from S3 as and when it’s required, which for large tables can cause some initial slowness and quite a lot of I/O.

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_RestoreFromSnapshot.html

To help mitigate the effects of lazy loading on tables to which you require quick access, you can perform operations that involve full-table scans, such as SELECT *. This allows Amazon RDS to download all of the backed-up table data from S3.