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From Ard Schrijvers <a.schrijv...@onehippo.com>
Subject Re: Searching for a property
Date Fri, 18 Dec 2009 08:57:59 GMT
Hello Dennis,

On Thu, Dec 17, 2009 at 9:50 PM, Dennis van der Laan
<d.g.van.der.laan@rug.nl> wrote:
> Could this mean that there is not enough memory for the Lucene indexes
> and the indexes are read from disk all the time?

The problem is not Lucene: if Lucene is slow, the problem is in *how*
Lucene is used.

> Any idea how large the indexes will become? I have no idea how the

Depends on the size of your repository. We have sizes of around 20 Gb.
Depending on what your queries are, you are fine

> internals of Lucene look like. The virtual paths have an average string
> length of about 50 characters and we end up having about 1 million of
> these properties.

Depending, again, on how you query this will lead to large memory
consumptions. If you sort on it for example. Internally in Lucene a
lot of memory is taken for it, and in Jackrabbit again. So, 50 chars,
4 byte a char (?) * 10^6 * 2  = 400 Mb...

> Thanks for any help!

See next mail :-))

Regards Ard

> Dennis
>>> A related question: could it be that when a query returns no results,
>>> this is slower than when it does return a result? Might it have
>>> something to do with Lucene not having an index for that particular
>>> property value?
>> No, an inverted index structure does not suffer from this
>> Regards Ard
>>>> Hello Dennis,

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