Comments on: Property Extraction in FS4SP

By: John O'Reilly

John O'Reilly — Mon, 14 Mar 2011 01:28:29 +0000

Hi, thanks for posting! I had been using dictionary extractors with custom people and locations lists, this is great.

I did run across a strange behaviour, though, when I try to have a refiner for a property mapped to wholewordsx on the same refinement panel as one mapped to a pipeline extensiblity extracted property. It seems unbelievable but I reproduced it in two completely different environments. I can have my three refiners mapped to the wholewords dictionary extractors OR I can have my 6 refiners mapped to custom properties extracted with an extensibility component. The data is there in both cases, and it fails if I have just one of each kind.

Just wondering if you’ve seen anything like that?

Many thanks,

John.

By: Steen Westergaard

Steen Westergaard — Thu, 03 Mar 2011 17:31:04 +0000

It’s a little bit tricky to see whether a crawled property is multi-valued as the multi-valued field in the GUI is set to false even the property has a multi-valued value. Looking at the CrawledProperty Class, it does not contain a multi-valued property. Retrieving a crawled property through PowerShell you can see that it has an IsMultiValued property that is read only but it is still set to false even the content is multi-valued. The safe way to see if crawled property is multi-valued is to check the content and see if it contains a separator char i.e. a 0×2029

By: Mikael Svenson

Mikael Svenson — Thu, 03 Mar 2011 11:33:36 +0000

I agree that it’s not an easy find. But if you read the remarks on TechNet it says: This property must also be set to [true] to include all values from a multi-valued crawled property. If set to [false] it would only include the first value from a multi-valued crawled property.

I learned it myself by looking at the config for location and people managed props, not by reading the docs ;)

By: Steen Westergaard

Steen Westergaard — Thu, 03 Mar 2011 10:09:02 +0000

Thanks Mikael, with MergeCrawledProperties = true it works fine. It is a little bit confusing that MergeCrawledProperties is called “Include values from all crawled properties mapped” in the GUI when you only want to map to one crawled property.

By: Trond Øivind Eriksen

Trond Øivind Eriksen — Thu, 03 Mar 2011 08:44:55 +0000

Thanks for the comment, Steen. Please let me know if Mikael’s approach doesn’t work. I might just have another trick up my sleeve.

By: Mikael Svenson

Mikael Svenson — Thu, 03 Mar 2011 08:21:58 +0000

Steen, make sure the managed property where you map your wholeword crawled properties have MergeCrawledProperties = true. If not you will only get one value.

By: Steen Westergaard

Steen Westergaard — Wed, 02 Mar 2011 21:49:33 +0000

Great article – In addition to the out of the box extractors I have used the custom extractor Wholewords1 where you can build your own dictionary from scratch. Compared to the out of the box extractors I found a least one big disadvantage using a custom extractor. When you for example have two dictionary entries (key, value) Wine,Wine and Chardonnay,Chardonay and you use both keys in a document, you only get a refiner values for one of the values which in my opinion makes it useless for searching. I know that dictionary keys are case sensitive and ensured to have an exactly match in my document.

I have tried to add some new keys to the Person names extractor and it works fine with multiple key values in a document.

Do you have any experience with custom extractors and do you know how to get around the problem described above?