By default, all stemming dictionaries are applied to all other vocabularies. There is no option available to select more precisely which stemming dictionaries must be applied to one given thesaurus.
Thesaurus entries may be quite long depending on the scope to cover. In this case, indexing documents may take a while and may significantly lengthen the overall time of document processing.
From the Back Office Technical Configuration, the following option:allows to discard entries exceeding more than a given amount of words.