Re: How many is too many

From: Greg Rahn <greg_at_structureddata.org>
Date: Thu, 11 Aug 2011 17:03:12 -0700
Message-ID: <CAGXkmisOBjK1XfPjKD18tewWT_fhbLtYoZ9++DGOh=c+hhcctg_at_mail.gmail.com>

Sounds like the "index death spiral" to me. My simple sanity check: when the total number of columns indexed is greater than the number of columns in the table, there is likely a design or tuning problem. Often times, even before then...

On Thu, Aug 11, 2011 at 1:45 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.
>

-- 
Regards,
Greg Rahn
http://structureddata.org

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Received on Thu Aug 11 2011 - 19:03:12 CDT