Does anyone have similar issues?
I had similar issues on different instance types. The trend of swapping stays even if you would switch to higher instance type with more memory.
An explanation from AWS you can find here
Amazon RDS DB instances need to have pages in the RAM only when the pages are being accessed currently, for example, when executing queries. Other pages that are brought into the RAM by previously executed queries can be flushed to swap space if they haven't been used recently. It's a best practice to let the operating system (OS) swap older pages instead of forcing the OS to keep pages in memory. This helps make sure that there is enough free RAM available for upcoming queries.
And the resolution:
Check both the FreeableMemory and the SwapUsage Amazon CloudWatch metrics to understand the overall memory usage pattern of your DB instance. Check these metrics for a decrease in the FreeableMemory metric that occurs at the same time as an increase in the SwapUsage metric. This can indicate that there is pressure on the memory of the DB instance.
What is the maximum swap space?
By enabling Enhanced Monitoring you should be able to see OS metrics, e.g. The amount of swap memory free, in kilobytes.
See details here
