Igniters, I've found that we can't use SORTED index only for cache with String values. FULLTEXT index has always being created in IgniteH2Indexing.TableDescriptor.createIndexes().
I've create a ticket IGNITE-4715 [1]. Serji, please, take a look at this. [1] https://issues.apache.org/jira/browse/IGNITE-4715 -- Best regards, Andrey V. Mashenkov
