filed type for text search

[Xiao Li]

I have used Solr 3.4 for a long time. Recently, when I upgrade to Solr 4.0
and reindex the whole data, I find that the fields which are specified as
string type can not be searched by q parameter. If  I just change the type
to text_general, it works.  So my question is for Solr 4.0, must I set the
field type of text_general for text search?