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From Pradeep Singh <pksing...@gmail.com>
Subject Re: IndexSearch very slow after reopening the index
Date Thu, 14 Oct 2010 10:27:50 GMT
Many times when you run a search for the first time it has to load all field
values IF the field is being sorted on. Subsequent searches use that cache
and are faster. Does that happen in your case? From your description it
doesn't look like you are sorting, although this kind of performance
degradation would usually happen on first time sorts.

On Thu, Oct 14, 2010 at 3:03 AM, subwayne <labrassbandito@googlemail.com>wrote:

>
> Hi Ian,
>
> thank you for your quick response. I am running Lucene on Ubuntu 10.04, 64
> bit. I switched from MMapDirectory to NIOFSDirectory without any
> significant
> changes in performance. The Lucene version running is 3.0.2. I followed
> your
> advice and opened the IndexSearcher after I added all documents to the
> index. Now, the search performance is slow, too.
>
> I am indexing a vast amount of the Open Directory Project; in particular
> 60,000 categories with about 1,400,000 documents. Each document is
> represented by the short description made available bei ODP. Finally, the
> index on hard disk is rather small---408 MBytes.
>
> Regarding the NumericRangeQuery: It's true that I am only interested in an
> exact match. However I found on some forum, that one can use the
> NumericRangeQuery for exact matches as well without any performance loss.
> Nevertheless, I am willing to learn how such an exact match can be don more
> efficiently.
>
> While searching with Lucene, I pose about 100 queries like in my first post
> for each category.
>
> Last but not least, I installed VisualVM as an Eclipse Plugin. But I am not
> familiar with it and need to play with it a little bit.
>
>
> Ian Lea wrote:
> >
> > Do the fast searches that you get while the app is running use the
> > searcher you create before you add all the docs to the index?  Surely
> > that won't see the added docs.
> >
> > There are general tips on speeding up searches at
> > http://wiki.apache.org/lucene-java/ImproveSearchingSpeed.  There are
> > some gotchas with MMapDirectory depending on your OS and whether you
> > are 32 or 64 bit - see the javadocs.  What are you running? What
> > happens when you use a standard disk based directory rather than MMap?
> >  How many docs are you adding?  How big is the index?  What version of
> > lucene are you using?
> >
> > Your NumericRangeQuery doesn't look much like a range but I doubt
> > that's the problem.
> >
> > Finally, you could run a profiler to see where the time is being spent.
> >
> >
> > --
> > Ian.
> >
> --
> View this message in context:
> http://lucene.472066.n3.nabble.com/IndexSearch-very-slow-after-reopening-the-index-tp1699711p1699956.html
> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>
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