Re: How can I make PosgreSQL use an Index ?

Rhaoni Chiu Pereira wrote:

> Hi list,
>
> I have a table like this:
>
> CREATE TABLE "gsames00" (
> "ano_mes" varchar(6) NOT NULL,
> "descricao" varchar(30),
> PRIMARY KEY ("ano_mes")
> );
>
> and an index like this:
>
> CREATE INDEX GSAMES01 ON GSAMES00 (ANO_MES);
>
> When I run a explain analyze with this where clause:
>
> ... gsames00.ano_mes = to_char(ftnfco00.data_emissao,'YYYYMM') AND ...
>
> ftnfco00.data_emissao is a timestamp. When I run the explain analyze it says:
>
> ...
> -> Seq Scan on gsames00 (cost=100000000.00..100000006.72 rows=372 width=10)
> (actual time=0.01..0.96 rows=372 loops=19923)
> ...

looking at the cost I guess that you never run vacuum analyze on your
table, do it and let us know.

Regards
Gaetano Mendola