Eviction pass generation is the number of the eviction pass which is recorded into the page when the page is considered for eviction. At any point in time it indicates how many passes ago a page has been looked at by eviction server. The range of these numbers and a histogram are indicators of how well Eviction server is performing.

Collecting these stats requires to scan all pages in all trees which is an expensive operation.

However, checkpoint does it anyway. We can use checkpoints to collect these stats.