I just changed the backend from sqlite to postgres. When using the 
sqlite backend if I do an issue search on 'title' and enter xyz, the 
search results show all %xyz% (as in LIKE) title matches ignoring case. 
Doing the same thing when using the postgres backend, the search results 
only show records that have an exact LIKE match with %xyz%. I ran into 
this with another program and wrote a insensitive_like function to 
handle the differences between MySQL, sqlite and Postgres. MySQL and 
sqlite do a case insensitive LIKE, but with Postgres one has to use 
ILIKE.

I searched the roundup/ code and only found one place where LIKE was 
being used in a database context: ./backends/rdbms_common.py:2437. That 
code didn't put %'s around the search string so that wasn't it. Sorry I 
wasn't able to determine where the problem was to provide a patch.