From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
---|---|
To: | Mark Harrison <mh(at)pixar(dot)com> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: implicit index created, do I need to also create an explicit index? |
Date: | 2005-11-19 09:50:51 |
Message-ID: | 20051119095042.GA8630@svana.org |
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Thread: | |
Lists: | pgsql-general |
On Fri, Nov 18, 2005 at 01:38:59PM -0800, Mark Harrison wrote:
> So I create a table with unique fields, and it creates an implicit index.
>
> 1. This is a general purpose index, correct? I.e. not used solely for
> ensuring uniqueness, so I don't need to create another index on
> the same field explicitly, right?
Right
> 2. What are the implications of creating another index, such as
> create index foo on tv_workspace(name)? Is is just a duplicate
> of the implicitly created index?
Well, if one is unique and the other isn't, they're not quite
identical. But the latter is redundant and probably won't ever be
used...
Have a nice day,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.
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