Guru's Guide to SQL Server Architecture and Internals, The

Generations

Each row tracked in MSmerge_contents and MSmerge_tombstone is assigned a generation number. A generation is a simple integer column that functions as a sort of logical clock that enables the Merge Agent to determine when a change was made to a row and how the time of that change relates to changes to the same row made by other parties in the replication scenario. An integer rather than a datetime value is used because it avoids having any sort of dependency on synchronized clocks between sites and is more resilient to common intersite issues such as time zone differences.

Only one row is maintained in MSmerge_contents for each row inserted or updated in a table. Each time a row is updated, its generation number is updated in MSmerge_contents ...