Indexing the t_name.name field, I can increase speed, but only if I restrict my search to something like : select * from t_name where t_name.name like 'my_search%' (In this case it takes generally less than 1 second) My question : Are there algorithms or tools that can speed up such a type of queries ("like" condition begining with a "%" symbol) ?
Apart from indexing the field you could use full text indexing. See http://techdocs.postgresql.org/techdocs/fulltextindexing.php
What other types of queries are you running that you want to speed up ?