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From Marcel Reutegger <marcel.reuteg...@gmx.net>
Subject Re: Jackrabbits own FileSystem and unit tests
Date Thu, 31 Aug 2006 17:13:11 GMT
Christoph Kiehl wrote:
> I like the idea of having a transactional index but I don't think it's a 
> good idea to read this index from a binary property in a database, 
> because in our case we've got a fairly large repository where we got 
> index files with a size of 40MB. As far as I understand you have to 
> transfer 40MB to the database on every index change that gets committed. 
> Am I right?

In general, this is correct. but lucene is designed in a way that it 
never modifies an existing index file. if you have a 40 MB index 
segment file and you delete a document within that index, lucene will 
simply update a small other file which is kept along the index called 
<segment-name>.del. Adding a new document to an existing index segment 
is not possible, in that case lucene will create a new segment.

in practice this would mean that an index segment file is read from 
the persistence manager (e.g. database) only once and then deleted at 
some point when the index merger created a new index segment from 
existing ones.

regards
  marcel

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