With the move to truncate markers we want to also keep track of the time spent performing truncation and the earliest wall time seen during truncation. This will help us detect possible issues with the system clock or clock shifts that prevent removal.

The requirements for this are to record metrics similar in nature to change collection metrics:

• Total time spent removing
• Total passes done
• Bytes deleted
• Docs deleted
• Collections scanned
• Max wall clock seen in the preimage collection

For multi-tenant environments this will be an aggregation between all the tenants so that one pass equals a scan on every tenant.