Hello Ard,

We rewrote a part of our virtual path handling, and now store both the
virtual path itself, and the lower-case equivalent (we really need the
not-lowercased path). All queries are now done on the lowercased virtual
path and indeed (!) everything stays fast, even after a million virtual
paths. We'll try to keep away from the lower-case function and similar
functions.

Thanks very much for all your help!

Dennis

Ard Schrijvers wrote:
> On Thu, Dec 17, 2009 at 10:59 PM, Dennis van der Laan
> <[email protected]> wrote:
>   
>> Dennis van der Laan wrote:
>>     
>
>   
>> See the increase of time spent on the execution: 400+ ms instead of 7ms.
>> And this is not a single incident, I see this increase on all queries
>> like the above.
>>
>> The memory of the JVM should not be a problem, it's set to 2Gb and only
>> 800Mb is used at the moment the queries are slow. Restarting the
>> application does not help either.
>>     
>
> No, this seems logical to me. The memory is consumed by internal
> lucene term enums. I am quite sure what your issue is, but did not
> test it, nor ever tried it myself. But, I have always wondered *how*
> the fn:lower-case could have been implemented efficiently in
> Jackrabbit. It doesn't fit into my understanding of how inverted
> indexes work, what Lucene is in the end. So, I am happy that my
> understanding was correct, and unhappy that fn:lower-case does (again,
> from top of my head and looking at code only) not scale to well.
>
> I think in your setup a lot of time is spend in the CaseTermQuery,
> which traverses all your 1 million virtualpaths first and lowercase
> it. This cannot scale (nor in cpu, nor in memory).
>
> So, would you like to give me an indication about the query execution
> time without the fn:lower-case? I think it will drop to < 1 ms.
>
> I think you should try to get away without using the fn:local-name if
> this works for you. Just make sure that you store the virtualpath
> property always as lower-case: then, you are fine
>
>   
>> Again, any help will be appreciated.
>>     
>
> let me know if this helped,
>
> Regards Ard
>
>   
>> Dennis
>>
>>     
>>>> Furthermore, of course, index size matters as well
>>>>
>>>>         


-- 
Dennis van der Laan

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