Best way to get X last messages from the set

Client Libraries C# Client
1

What would be the most performant way to get last records in a particular set? Our use case requires us to retrieve the tail of the set, say 100 last records written.

2

There isn’t any notion of order in an Aerospike set or namespace. That said, if you write to the set with a TTL and that TTL is always the same, you could:

scan the set for meta data only (the meta data is in RAM on Aerospike)
Filter out the N largest TTLs
Do a batch read on these N records

This would return the N most recently updated/written records.