CD Instance is configured for Private session but Redis is showing keys for both Shared and Private Session

Question

Our CMS instance is using "In Process" session state and CD instance is using "Out of Process" session state. We have configured it for private session state using Sitecore ASP.NET Session State Provider for Redis. Whenever a new session getting created in CD site both shared and private session keys getting created in Redis like below:-

{shared_e2e3c7dc-0d13-41cc-b96c-96845e72fc72}_Data
{shared_e2e3c7dc-0d13-41cc-b96c-96845e72fc72}_Internal
{shared_2249c582-2786-4628-a0e2-e7d72514f552}_Data
{shared_2249c582-2786-4628-a0e2-e7d72514f552}_Internal
shared_ExpirationIndex

{private_zepnhiqm41wolw23gkve3flu}_Data
{private_zepnhiqm41wolw23gkve3flu}_Internal
{private_hnwxf5w1vb1v2adwaxxm40de}_Data
private_ExpirationIndex

I have below doubts:-

1. If I have configured for private session state, why I am seeing shared session keys?
2. In one of our non production environment I am seeing 20K such keys. I am doubting if these are getting cleaned up or not. So I want to understand how these gets cleaned up?

Thanks

Answer 1

I raised a ticket to Sitecore for the same. I have received and verified that answer. On session end, its data is being committed to xConnect and removed from the session storage.