Handling regular expressions

However, this is still not everything. Trigram indexes are even capable of speeding up simple regular expressions. The following example shows how this can be done:

test=# SELECT * FROM t_location WHERE name ~ '[A-C].*neu.*'; 
     name      
-------------- 
 Bruckneudorf 
(1 row)

test=# explain SELECT * FROM t_location WHERE name ~ '[A-C].*neu.*'; 
                                 QUERY PLAN                                  
----------------------------------------------------------------- 
 Index Scan using idx_trgm on t_location  (cost=0.14..8.16  
   rows=1 width=13) 
   Index Cond: (name ~ '[A-C].*neu.*'::text) 
(2 rows)

PostgreSQL will inspect the regular expression and use the index to answer the question.