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From Michael Wechner <michael.wech...@wyona.com>
Subject Re: Scalable Domain
Date Thu, 23 Oct 2008 07:51:58 GMT
Jukka Zitting schrieb:
> Hi,
>
> On Thu, Oct 23, 2008 at 9:10 AM, Michael Wechner
> <michael.wechner@wyona.com> wrote:
>   
>> Bertrand Delacretaz schrieb:
>>     
>>> Storing one million nodes should not be a problem, but you'll need to
>>> use a structure where no parent node has more than about 10k child
>>> nodes.
>>>       
>> just being curious, but where does this number come from?
>>     
>
> It's a rough estimate I once made based on some ad-hoc experiments I
> made. The exact numbers of course vary per platform, but the problems
> typically start to manifest themselves somewhere within the 1k-100k
> range, with 10k being a good rule of thumb that I like to use when
> evaluating designs for content hierarchies.
>   

ok
>   
>> AFAIK the filesystems ext2 and ext3 (http://en.wikipedia.org/wiki/Ext3) have
>> about 32'000 as limit, so I guess the question is how many files per jackrabbit
>> node are needed?
>>     
>
> That depends on the persistence manager you use. None of the standard
> persistence managers hits the underlying file system limits in terms
> of child nodes, the issue is more about the size of the persisted
> parent node state. All the persistence managers currently store the
> names and identifiers of all the child nodes inside the serialized
> node state blob, so the more child node entries you have the slower it
> will be to read or write the parent node state. At some point you'll
> also start hitting things like BLOB size limits in persistence
> databases.
>   

ok
> Caching typically takes away some of the pain related to large node
> states, but things like adding or removing a child node become
> increasingly slower the bigger the parent node is.
>   

thanks for this info

Michael
> BR,
>
> Jukka Zitting
>   


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