Re: Need help on index!!!

Try single quotes around 10000:

select * from pmmeasure where dataid = '10000';

This is understood to mean:

select * from pmmeasure where dataid = '10000'::bigint;

Without the quotes this is understood to be

select * from pmmeasure where dataid = ('10000'::int4)::bigint;

which is not what you want anyway.


Dan Weston


On Fri, 21 Jun 2002, Johnson Ma wrote:

> Hi guru
>
> I have a table with 300,000 records. I also created a index on it. But
> the postgresql use sequence scan every time, when i search one record.
> It is so slow. why?
>
> here is create table script
> create table pmmeasure (dataid bigint not null,
>                      measurenum bigint DEFAULT nextval('measurenum')
> UNIQUE NOT NULL,
>                      name  varchar(100) not null,
>                      value varchar(100) not null,
>                      constraint pk_pmmeasure primary key (measurenum),
>                      constraint fk_pmmeasure_1 foreign key (dataid)
> references pmdata (dataid)
>  );
> create index index_pm on pmmeasure (dataid);
>
>
> When I do like
> explain analyze select * from pmmeasure where dataid = 10000;
>
> it shows that postgresql always sequence scan for that record.
>
>
> Thanks a lot.
>
>
> Johnson
>
>
>
>
>
>
>
>
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