Index Statistics

I am toying around with the article below to try to get my brain around some
index tuning issues and understand how to apply the knowledge to our
database.
http://www.sql-server-performance.c..._statistics.asp
So I did a DBCC SHOW_STATISTICS on one of our larger indexes, and I don't
understand these results:
Range-Hi-Key Range-Rows Eq-Rows Distinct-Range-Rows Average-Range-Rows
BASFITSERVICES 664.69312 683.0 0
974.95349
If Range-Rows is how many items mapped to this index key and Eq-Rows
represents how many items are equal to this index key, then how can Eq-Rows
be greater, and why would the Average be even higher?
--
Peace & happy computing,
Mike Labosh, MCSD
"(bb)|(^b{2})" -- William ShakespeareHi Mike
I think you have not quite understood the values being returned!
From BOL:
RANGE_HI_KEY Upper bound value of a histogram step.
RANGE_ROWS Number of rows from the sample that fall within a histogram step,
excluding the upper bound.
EQ_ROWS Number of rows from the sample that are equal in value to the upper
bound of the histogram step.
DISTINCT_RANGE_ROWS Number of distinct values within a histogram step,
excluding the upper bound.
AVG_RANGE_ROWS Average number of duplicate values within a histogram step,
excluding the upper bound (RANGE_ROWS / DISTINCT_RANGE_ROWS for
DISTINCT_RANGE_ROWS > 0).
You may also want to look at the pages on this in "Inside SQL Server 2000"
by Kalen Delany ISBN 0-7356-0998-5
John
"Mike Labosh" wrote:

> I am toying around with the article below to try to get my brain around so
me
> index tuning issues and understand how to apply the knowledge to our
> database.
> http://www.sql-server-performance.c..._statistics.asp
> So I did a DBCC SHOW_STATISTICS on one of our larger indexes, and I don't
> understand these results:
> Range-Hi-Key Range-Rows Eq-Rows Distinct-Range-Rows Average-Range-Ro
ws
> BASFITSERVICES 664.69312 683.0 0
> 974.95349
> If Range-Rows is how many items mapped to this index key and Eq-Rows
> represents how many items are equal to this index key, then how can Eq-Row
s
> be greater, and why would the Average be even higher?
> --
> Peace & happy computing,
> Mike Labosh, MCSD
> "(bb)|(^b{2})" -- William Shakespeare
>
>|||Thanks, John!
Mike, you might also want to look at this whitepaper:
http://msdn.microsoft.com/library/d...r />
query.asp
HTH
--
Kalen Delaney
SQL Server MVP
www.SolidQualityLearning.com
"John Bell" <JohnBell@.discussions.microsoft.com> wrote in message
news:D09E0695-CBD6-4B33-BF3F-E5DCF6B4B294@.microsoft.com...
> Hi Mike
> I think you have not quite understood the values being returned!
> From BOL:
> RANGE_HI_KEY Upper bound value of a histogram step.
> RANGE_ROWS Number of rows from the sample that fall within a histogram
> step,
> excluding the upper bound.
> EQ_ROWS Number of rows from the sample that are equal in value to the
> upper
> bound of the histogram step.
> DISTINCT_RANGE_ROWS Number of distinct values within a histogram step,
> excluding the upper bound.
> AVG_RANGE_ROWS Average number of duplicate values within a histogram step,
> excluding the upper bound (RANGE_ROWS / DISTINCT_RANGE_ROWS for
> DISTINCT_RANGE_ROWS > 0).
> You may also want to look at the pages on this in "Inside SQL Server 2000"
> by Kalen Delany ISBN 0-7356-0998-5
> John
>
>
> "Mike Labosh" wrote:
>|||Of course if you are in the UK on 8th or 10th Feb and wish to hear the
master herself then check out http://www.sqlserverfaq.com/
John
:):)
Kalen Delaney wrote:
> Thanks, John!
> Mike, you might also want to look at this whitepaper:
>
>
http://msdn.microsoft.com/library/d...l/statquery.asp
>
> --
> HTH
> --
> Kalen Delaney
> SQL Server MVP
> www.SolidQualityLearning.com
>
> "John Bell" <JohnBell@.discussions.microsoft.com> wrote in message
> news:D09E0695-CBD6-4B33-BF3F-E5DCF6B4B294@.microsoft.com...
histogram
the
step,
histogram step,
Server 2000"
around
our
http://www.sql-server-performance.c..._statistics.asp
I don't
Eq-Rows
can|||And thanks again...:-)
HTH
--
Kalen Delaney
SQL Server MVP
www.SolidQualityLearning.com
"John Bell" <jbellnewsposts@.hotmail.com> wrote in message
news:1106676698.587786.264330@.f14g2000cwb.googlegroups.com...
> Of course if you are in the UK on 8th or 10th Feb and wish to hear the
> master herself then check out http://www.sqlserverfaq.com/
> John
> :):)
>
> Kalen Delaney wrote:
> http://msdn.microsoft.com/library/d.../>
atquery.asp
> histogram
> the
> step,
> histogram step,
> Server 2000"
> around
> our
> http://www.sql-server-performance.c..._statistics.asp
> I don't
> Eq-Rows
> can
>