How to retrieve real time data coming from tranquility

We did an emergency upgrade from 0.21.1 to 0.22.2 version of Druid recently owing to log4j security patch. It is a single large server deployment. We get API requests through Tranquility in real time to a table. Derby is used for metadata and deep storage is located in /var directory. Granularity is set to day.
As part of the upgrade we followed below steps.

  1. Terminated Tranquility and Druid servers
  2. Copied /var folder from existing druid to new version of druid
  3. moved old version of druid(0.21.1) to other directory and new version (0.22.2) is set to active druid
  4. Started druid and tranquility servers

Everything worked fine but we lost real time data for that particular day. I understood it late that the real time data is stored in memory and we might have lost it when we stopped the server. Is there any way we can retrieve the data for that one particular day?

Have you checked out this page? tranquility/overview.md at master · druid-io/tranquility · GitHub