We have noticed that when results in Solr are tied, they are sorted differently across different instances. How can we make sure that they are sorted in the same way?
Whenever there is a scoring tie in the search results Solr will use the internal docID value as a tie-breaker. The issue here is that the docID values do not match across instances, and the sorted results will be different as well.
To avoid this issue you could add a secondary field to the sort parameter, which will then ensure that the results are consistent across different instances.
For instance, to sort by name after a tie happens, use the following:
&sort=score desc, name asc