Get title length statistics from within Raven Studio

[Ben]

Hey guys,

I wrote a quick index to pull out some stats on total lengths in our database and I'm getting very odd results:

Map:

from p in docs.Projects

select new {

TitleLength = p.Title.Length,

MaxLength = 0,

MinLength = 0,

Count = 1

}

Reduce:

from result in results

group result by 0 into g

let totalLength = g.Sum(x => x.TitleLength)

let totalCount = g.Sum(x => x.Count)

let maxLength = g.Max(x => x.TitleLength)

let minLength = g.Min(x => x.TitleLength)

select new {

TitleLength = totalLength / totalCount,

MaxLength = maxLength,

MinLength = minLength,

Count = totalCount

}

The results are very odd indeed:

{

  "TitleLength": 1.896636619018431E-05,

  "MaxLength": 0.10686838081350422,

  "MinLength": 0.0709223358532835,

  "Count": 9374.0

}

Am I doing anything wrong here?

[Tal Weiss]

Each time you reduce you divide by the current count. You are driving multiple times.

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[Tal Weiss]

Let's say you got two steps of reduce each reduce has 10 items and total of 100. The length of all titles is 10. So 10*10/10=10 life is good. Than 10*10/100=1 life isn't so good. I would add a field that is total/count and not assign total=total/count it is just not right.