Re: How many is too many

From: Ram Raman <veeeraman_at_gmail.com>
Date: Thu, 11 Aug 2011 22:14:45 -0500
Message-ID: <CAHSa0M0zL6W0r62b8JEqxCmALwwJcOmiNBG5PUsfaAoeid13=A_at_mail.gmail.com>

Rule of thumb! Thanks for the response Greg. Does this apply to Data warehouse or OLTP applications or both?

On Thu, Aug 11, 2011 at 7:03 PM, Greg Rahn <greg_at_structureddata.org> wrote:

> 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 - 22:14:45 CDT