Re: How does Index Scan get used

"Samuel J. Sutjiono" <ssutjiono(at)wc-group(dot)com> writes:
> create table test (test_col text);
> create index test_index on test (test_col);
> insert into test values ('abc.xyz');
> insert into test values ('abcxyz');
> insert into test values ('abc/xyz');

> explain select * from test where test_col like 'abc/%';

> NOTICE: QUERY PLAN:

> Seq Scan on test (cost=3D0.00..22.50 rows=3D10 width=3D12)

I did the above and got:

regression=# explain select * from test where test_col like 'abc/%';
NOTICE: QUERY PLAN:

Index Scan using test_index on test (cost=0.00..17.07 rows=5 width=32)

Perhaps you are using a locale that prevents LIKE from being optimized
into an indexscan? See
http://www.ca.postgresql.org/users-lounge/docs/7.2/postgres/charset.html#AEN16601

regards, tom lane