Re: How many is too many

  • From: Greg Rahn <greg@xxxxxxxxxxxxxxxxxx>
  • To: veeeraman@xxxxxxxxx
  • Date: Thu, 11 Aug 2011 17:03:12 -0700

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@xxxxxxxxx> 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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