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From Mark Bennett <>
Subject Re: relative document path in lucene index
Date Sat, 05 Apr 2014 21:36:49 GMT
As I understand it (?), there are 2 technical things you’re asking about:

1: Can you move an index from one place to another, a different disk or drive letter, CD,
etc - Generally yes, this is allowed.

2: Can you alter the path names stored within the index - in some cases yes, but I was suggesting
a 2 index solution.

Taking each in turn:

For item 1, moving an index.  A Solr “core” includes its configuration and its index data.
 The paths are almost always relative; all the cores sit under a common “solr home” directory,
and they can be moved, copied, zipped/unzipped, etc.

With Lucene, the coder has more control so things can vary, but within the base index directory
I don’t believe there’s any absolute path names; all the files are in the same index directory.
 So unless something very unusual has been done, it should be OK to move the files as a set.

For item 2, Solr lets you update specific fields in a document.  But in the background, it’s
actually still doing a full reindex, but for any fields you don’t update it copies and reindexes
them from the old copy.  I believe these Solr calls map to Lucene calls, and therefore should
generally be the same rules.  This requires that fields be stored.  So you could do this with
1 index.  My only concern was that, with 1 index, you might only get one chance to get it
right; the 2 index solution gives you some insurance to retry, iterate, adjust, etc.

Mark Bennett / LucidWorks: Search & Big Data /
Office: 408-898-4201 / Telecommute: 408-733-0387 / Cell: 408-829-6513

On Apr 5, 2014, at 12:38 AM, spok <> wrote:

> Mark, thanks for your answer, I´m rather new, so let me explain what I
> understood ...
> Of course I can use solr within tomcat, move the whole server, and all will
> be ok.
> But is there a way to generate a lucene file system index at location "a"
> for data files at "a1", move index files and data files to a movable
> location like CD or USB stick, adapt index files to reflect the new
> conditions, and then read the index with carrot2 workbench (to my knowledge
> the only carrot2 implementation with Aduna clustering capabilities).
> What you propose is to have two lucene installations, and copy the index.
> But will this work on a movable file system like USB stick which can have
> different device letters?
> So please if your explanation is a solution for what I want to do, what
> should I read to catch the details? Thanks in advance
> --
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