Re: How many is too many

From: Toon Koppelaars <toon.koppelaars_at_rulegen.com>
Date: Fri, 12 Aug 2011 07:23:49 +0200
Message-ID: <CAA9w=Es8DjCVC45hhv_iG8vF0Oi3nM45YG_nRv6gGQYTKcJ4ww_at_mail.gmail.com>



Tables with that many indexes, to me, are usually a strong sign that the table holds multiple 'entity types', and in fact should have been designed as multiple tables. I bet that there are a lot of NULL-able columns in that table too, right?

The fact that you mention 'third party product', by the way, is a sign in that direction too :-)

On Thu, Aug 11, 2011 at 10:45 PM, Ram Raman <veeeraman_at_gmail.com> wrote:

> Listers,
>
> I am looking at a table in our system and it has 12 indexes, we are
> planning on adding another one. I am aware of the effects of having too many
> indexes, but in this case adding an extra index helps a certain query that
> runs slow. Other queries and most other operations against the table
> are acceptable too. I see a few tables like this; is there a number above
> which is considered a no-no when it comes to adding more indexes.
>
> PS. The tables and queries are structured in a way that seem to require
> several indexes - it is a third party product.
>
> TIA,
> Ram.
>

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Toon Koppelaars
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(co)Author: "Applied Mathematics for Database Professionals"
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Received on Fri Aug 12 2011 - 00:23:49 CDT

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