The migration agent feature which helps migrate from repository 2 to repository 3 includes a user editable feature setting to alter the changelog batch size fetched from repository 2.
The default value is 100 records.
The primary reason this is configurable is to tune efficiency of the overall migration process.
In particular, in the case of migrating NPM format repo content, the batch size may need to be tuned down in order to create changelog payloads of a reasonable size - this has been known to avoid causing OutOfMemory situations in NXRM 2 while migrating.
On the other hand, other repo formats may benefit from having the batch size be increased from say 100 to 200 or higher to make the overall migration process faster to complete. This is because the the changelog payload size is not increased significantly for those formats, plus the NXRM 2 side query to get the next batch of records won't be severely impacted by increasing the batch size in reasonable increments.
The batch size maximum allowed in NXRM 2 value is 1000.
Given the repo format being migrated may benefit from different batch size values, provide the ability to tune the batch size per format, or artificially limit the response payload size, irregardless of requested batch limit.