Re: Index scan is not working

On Mon, Sep 19, 2016 at 02:10:50PM +0200, Kiran wrote:

> EXPLAIN ANALYZE select * from question where weighted_tsv @@
> to_tsquery('Hur&ofta');
>
> I get the following output
>
> "Bitmap Heap Scan on question (cost=12.33..25.38 rows=10 width=731)
> (actual time=0.058..0.062 rows=3 loops=1)"
> " Recheck Cond: (weighted_tsv @@ to_tsquery('Hur&ofta'::text))"
> " Heap Blocks: exact=3"
> " -> Bitmap Index Scan on weighted_tsv_question_idx (cost=0.00..12.33
> rows=10 width=0) (actual time=0.052..0.052 rows=3 loops=1)"
> " Index Cond: (weighted_tsv @@ to_tsquery('Hur&ofta'::text))"
> "Planning time: 0.205 ms"
> "Execution time: 0.104 ms"
>
> Why the query is using the Bitmap ? Not the Index scan ?

You want PostgreSQL to use an index to try speed up a query
which takes 0.3 milliseconds to select 3 out of 10 rows ?

What is your exact workload that requires speedup of that
query ?

Karsten
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