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From robert engels <reng...@ix.netcom.com>
Subject Re: [jira] Commented: (LUCENE-565) Supporting deleteDocuments in IndexWriter (Code and Performance Results Provided)
Date Thu, 06 Jul 2006 19:24:13 GMT
I guess we just chose a much simpler way to do this...

Even with you code changes, to see the modification made using the  
IndexWriter, it must be closed, and a new IndexReader opened.

So a far simpler way is to get the collection of updates first, then

using opened indexreader,
for each doc in collection
       delete document using "key"
endfor

open indexwriter
for each doc in collection
       add document
endfor

open indexreader


I don't see how your way is any faster. You must always flush to disk  
and open the indexreader to see the changes.



On Jul 6, 2006, at 2:07 PM, Ning Li wrote:

> Hi Otis and Robert,
>
> I added an overview of my changes in JIRA. Hope that helps.
>
>> Anyway, my test did exercise the small batches, in that in our
>> incremental updates we delete the documents with the unique term, and
>> then add the new (which is what I assumed this was improving), and I
>> saw o appreciable difference.
>
> Robert, could you describe a bit more how your test is set up? Or a  
> short
> code snippet will help me explain.
>
> Without the patch, when inserts and deletes are interleaved in small
> batches, the performance can degrade dramatically because the  
> ramDirectory
> is flushed to disk whenever an IndexWriter is closed, causing a lot of
> small segments to be created on disk, which eventually need to be  
> merged.
>
> Is this how your test is set up? And, what are the maxBufferedDocs  
> and the
> maxBufferedDeleteTerms in your test? You won't see a performance
> improvement
> if they are about the same as the small batch size. The patch works by
> internally buffering inserts and deletes into larger batches.
>
> Regards,
> Ning
>
>
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