Don Isgitt <djisgitt(at)soundenergy(dot)com> writes:
> gds2=# explain select * from lg where section=14;
> NOTICE: QUERY PLAN:
> Seq Scan on lg (cost=0.00..5885.77 rows=3836 width=73)
> EXPLAIN
> gds2=# set enable_seqscan=off;
> SET VARIABLE
> gds2=# explain select * from lg where section=14;
> NOTICE: QUERY PLAN:
> Index Scan using lgsec on lg (cost=0.00..12167.45 rows=3836 width=73)
> EXPLAIN
Of course, the above only proves that the planner thinks the indexscan
will be slower ;-). You should try EXPLAIN ANALYZE to see how well the
planner estimates square up with reality ...
regards, tom lane