Re: Index scan is not working

Hi Karsten,

Thanks for the response.
I want to know whatever the Analyze output I am getting is normal for a
table having few records or something is wrong.
Will the DB engine uses whatever the best way to execute a query
irrespective of the indexing in this case?

At the moment the records in the table is very low but that column will be
in thousands of rows in the near future. hence I wanted to confirm from the
group am I doing something wrong here.

Also to_tsquery is casting to ::text. Is this normal ?

regards
Kiran

On Mon, Sep 19, 2016 at 2:33 PM, Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net>
wrote:

> 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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