Q:

Table indexes for autocomplete in MySQL

I need to implement an "autocomplete-like" query in MySQL, one on a fairly short textual field varchar(11) and one on a potentially long field varchar(140).
As they are autocomplete query, they will be LIKE-query. What sort of indexes I need to configure?

A:

not really big choice - it will be normal B-Tree index
with autocomplete You can not use FullText because it work only with full words
at the same time queries like:
SELECT text FROM tag_table WHERE text LIKE 'part_text%';

will use indexes 
add:
in case of big column - 
You of course could try to realise auto-complete by whole words - there You can create full text index, but not sure - how good it will work, because with fulltext always a lot of variants at the begin of search phrase, and variants how suggested text will be relevant to expected result

