Optimization for GetSecret with Azure Keyvault

Question

Our main goal for now is optimising the a processing service. The service has a system-assigned managed identity with accespolicies that allow to get a secret. This service makes 4 calls to a keyvault. The first one takes a lot longer than the others. I'm scratching my head, because the Managed Identity token takes 91µs to obtain. Application Insights image

I changed the way the tokens were obtained. The program only obtains it once and keeps using that same token for other round trips. I did this by making the CredentialClass AddScoped.

Answer 1

I assume the question is why the first call takes more time. If yes, just throwing in a couple of generic reasons which might contribute:

• HTTPS handshake on the first call might take time
• The client might need to create a connection pool
• In case of Azure Key Vault, the first call does two round-trips AFAIK, first for auth, the second for the real payload