[MarkLogic Dev General] Fragmentation boundary

[Michael Blakeley]

Right, and take a look at http://docs.marklogic.com/5.0doc/docapp.xqy#display.xqy?fname=http://pubs/5.0doc/xml/admin/fragments.xml if you want to know more about fragments. They are sometimes useful, but get a second opinion before configuring any fragment rules. Most applications do not need any fragment rules, and so their predicates never cross fragment boundaries (barring pathological cases like /a[doc()/b]).

Of course, Will happens to be working on an exception....

-- Mike

On 25 Apr 2012, at 11:23 , Will Thompson wrote:

> Danny,
> 
> You can configure fragments in the ML admin for your database under Fragment Roots or Fragment Parents. Basically, by configuring an element as a fragment, that element is treated as its own document in ML, so document roots and fragments will behave the same.
>  
> -Will
>  
> From: general-bounces at developer.marklogic.com [mailto:general-bounces at developer.marklogic.com] On Behalf OfDanny Sinang
> Sent: Wednesday, April 25, 2012 11:07 AM
> To: general
> Subject: [MarkLogic Dev General] Fragmentation boundary
>  
> I'm reading through the docs in  http://community.marklogic.com/pubs/5.0/books/performance.pdf and it says :
>  
> XPath predicates that cross fragment boundaries are unsearchable (cannot use indexes). 
>  
> For example, if a document is fragmented at the b element, then you should make sure predicates do not cross the b boundary. Therefore, the following expression:
>  
> /a/b[c="1"]/../d
>  
> will run faster than the following expression:
>  
> /a[b/c="1"]/d
>  
>  
> How do you determine / modify a document's fragmentation boundary ?
>  
> Regards,
> Danny
>  
>  
>  
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