Editting a content fragment model fails on 100000 node traversal

More specifically, when attempting to edit a content fragment model the process fails:

The query read or traversed more than 100000 nodes. To avoid affecting other tasks, processing was stopped.

After some investigation is looks like this query may be the culprit:

select [jcr:path], [jcr:score], * from [dam:Asset] as a where [jcr:content/contentFragment] = 'true' and 
[jcr:content/data/cq:model] = '/conf/we-retail/settings/dam/cfm/models/test' and 
isdescendantnode(a, '/content/dam') option(index tag [fragments]) 
/* xpath: /jcr:root/content/dam//element(*, dam:Asset)[(jcr:content/@contentFragment = 'true' and 
jcr:content/data/@cq:model = '/conf/we-retail/settings/dam/cfm/models/test')] option (index tag fragments) */

 On my server /content/dam is quite large.  Assuming this reference is indeed the problem, is it possible to change it?