I have \"text_general\" field in schema.xml
Sorting doesn't work good on multivalued and tokenized fields.
As testata
has been defined with text_general
field type, it will be tokensized and hence the sort would not work fine.
Sorting can be done on the "score" of the document, or on any
multiValued="false" indexed="true"
field provided that field is either non-tokenized (ie: has no Analyzer) or uses an Analyzer that only produces a single Term (ie: uses the KeywordTokenizer)
Source: http://wiki.apache.org/solr/CommonQueryParameters#sort
Use string
as the field type and copy the title
field into the new field.