Re: Dissapearing indexes, what's that all about?

Daniel ?erud <zilch@home.se> writes:
> and filling it with 10000 rows made out of
> $pwgen 8 10000 > data [enter]
> and then running VACUUM and VACUUM ANALYZE
> still yields a sequential scan doing a
> select * from index_with where name > 'm';
> namely
> seq scan on index_with (cost=0.00..189 rows 5170 width=16)

So?  You're asking it to retrieve over half of the table (or at least
the planner estimates so, and I don't see any evidence here that its
estimate is wildly off).  An indexscan would still be a loser in this
scenario.

If you want to see an indexscan with an inequality query, try giving
it a reasonably tight range.  Probably

select * from index_with where name > 'm' and name < 'n';

would use the index in this example.

            regards, tom lane