test=# create table dl6dbh (id serial primary key, val numeric);
CREATE TABLE
test=*# insert into dl6dbh (val) select random()*10000 from generate_series(1,100000) s;
INSERT 0 100000
test=*# create index idx_val on dl6dbh (val);
CREATE INDEX
test=*# commit;
COMMIT
test=# analyze dl6dbh ;
ANALYZE
test=*# explain analyse select * from dl6dbh order by val limit 100;
QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------
Limit (cost=0.42..5.63 rows=100 width=15) (actual time=0.038..0.138 rows=100 loops=1)
-> Index Scan using idx_val on dl6dbh (cost=0.42..5216.32 rows=100000 width=15) (actual time=0.037..0.127 rows=100 loops=1)
Planning Time: 0.187 ms
Execution Time: 0.156 ms
(4 rows)
test=*#