Date: Mon, 13 Sep 2021 12:36:31 +0200
From: hubert depesz lubaczewski <depesz@depesz.com>
Sender: depesz@depesz.com
To: puneet.orcl@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17189: Index not created when primary key created
Message-ID: <20210913103631.GB23362@depesz.com>
Reply-To: depesz@depesz.com
References: <17189-521a1b29d9727929@postgresql.org>
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On Mon, Sep 13, 2021 at 05:27:00AM +0000, PG Bug reporting form wrote:
> I have created the composite primary key which is created successfully but i
> am not getting the index against the primary key.

That's rather impossible. Please show create table statement, and output
of `\d table_name` after creation.

> When i created a select query and includes the primary key column it is
> going with full table scan. Even i am creating an index on the columns it is
> also going with full table scan.

Index will be used only when it makes sense.

If you'd do: select * from table; - that is select all rows - there is
no point in using index, as it will be slower than getting seq scan.

Plus - your table can be too small to effectively use index.

Consider reading:
https://www.depesz.com/2010/09/09/why-is-my-index-not-being-used/

Best regards,

depesz