From: | Dan Weston <ddweston(at)cinesite(dot)com> |
---|---|
To: | "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Need help on index!!! |
Date: | 2002-06-24 21:43:11 |
Message-ID: | Pine.LNX.4.33.0206241433090.30287-100000@musk.hollywood.cinesite.com |
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Thread: | |
Lists: | pgsql-general |
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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