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From Giulio Cesare Solaroli <giulio.ces...@gmail.com>
Subject Re: Deleting a document with an IndexWriter open
Date Fri, 16 Jul 2004 12:31:11 GMT
Hi Christoph,

On Fri, 16 Jul 2004 13:50:51 +0200, Christoph Goller
<goller@detego-software.de> wrote:
>[snip on good reasons why an IndexWriter can not delete documents]
> 
>> 
> If you want to do several updates at the same time, the most efficient
> way would be to:
> 
> 1) Keep an IndexReader/Searcher open on your index in order to guarantee
> reed access and a consistent index during the whole process.
> 
> 2) Open a new IndexReader and delete all the documents that you want to
> update.

This is the main problem; in my current arrangement, it is quite
difficult to find out the documents that needs to be updated in
advance; it would have been much easier to find out whether every
single document where a new entry or a document already present, and
thus to update (instead of insert).

I can try to work on finding a better way to list of updated
documents, but I was hoping to solve this problem with a different
route.

[...]
> > Do you confirm my idea that keeping and IndexWriter open as much as
> > possible while indexing batch of documents is a "good thing"?
> 
> Yes. IndexWriter works with a RamDirectory as cache. If you close
> it after each document and open a new one, you enforce unnecessary
> write operations to your hard disk.
> 
> > Is there any option to ever see a deleteDocument method in the
> > IndexWriter class
> 
> Probably not. I guess you either have to update every document separately
> as described in your email (open and close a reader and writer for each
> document), or do it in the way I describe above (more efficient).

I am not competent enough to suggest any possible solution for this
problem, but I hope that developers with required knowledge will take
this option into consideration for future versions of Lucene as it
will really simplify some tasks to the users.

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