In 2025.1, there are major changes to the configuration and maintenance of Enterprise Search. Those are outlined in KB0141034. As of the writing of this post, that KB article says that Incremental indexing is optional. In my opinion, it’s not.
As soon as you create the index, it will create CDC Subscriber rules for Enterprise Search. That will cause it to start writing records to cdc.capturelog. If you don’t have incremental indexing configured, those records will not get processed causing this table to grow.
Also, if you use custom BAQs in Enterprise search, be aware that deleting a BAQ may delete the subscriber rules for that BAQ table – eliminating changes to that table from updating Enterprise Search. In 2025.2.16, you can only see the rule by querying SQL and CDC Subscriber Maintenance won’t let you create any new rules. Not sure how long this has been broken.
The most efficient, supported way to deal with this problem is to save your custom search index as a template. Then if you end up with missing subscriber rules, you can delete the index and re-create the index using your template. This will get your index in place with the necessary CDC Subscriber rules and you don’t have to add/remove any BAQs from the index.
As far as I’ve been able to find – none of this is documented. 