Re: LIKE query on indexes

On Tue, 2006-02-21 at 09:57, Ibrahim Tekin wrote:
> hi,
> i have btree index on a text type field. i want see rows which starts
> with certain characters on that field. so i write a query like this:
>
> SELECT * FROM mytable WHERE myfield LIKE 'john%'
>
> since this condition is from start of the field, query planner should
> use index to find such elements but explain command shows me it will
> do a sequential scan.
>
> is this lack of a feature or i am wrong somewhere?

This is an artifact of how PostgreSQL handles locales other than ASCII.

If you want such a query to use an index, you need to back up your
database, and re-initdb with --locale=C as an argument. Note that you
then will NOT get locale specific matching and sorting.