Re: Recreating an index

DECAFFMEYER MATHIEU wrote:
> Hi, I have exactly the same question.
> Correct me if I'm wrong :
> it seems that I can do any I/O operations on the index
while querying
> because of the open IndexReader.
> 
> So if I had the same situation as gui (the poster of
the thread), I can
> just delete the old index while people query on it ?
> Then build a new index and re-open an indexreader on it
?

Opening an index dir with "create=true" while
readers are using it is
not well supported in Lucene currently.

I think it will work fine on UNIX ("delete on last
close" file
semantics), but on Windows you will get access denied errors
if
you try this.  The workaround is to make the new index in a
new path
and then swap readers over to that new path at a "good
time".

But some good news: this is now fixed in the trunk (not yet
in any
release but will be in 2.1 once it's released).  We re-use
the same
retry logic that's normally used by a writer when deleting
files, to
avoid problems with access denied errors on Windows.

Also, beware the deadly LUCENE-140:

     http:
//issues.apache.org/jira/browse/LUCENE-140

which causes silent index corruption if you use the wrong
"create =
true".  Both FSDirectory and IndexWriter take
"create" (this was
confusing and is also fixed in trunk).  You should use both
FSDirectory's "create=true" and IndexWriter's
"create=true" to prevent
that corruption.

Mike

> -----Original Message-----
> From: Guilherme Barile [mailto:guiprosoma.com.br] 
> Sent: Wednesday, January 31, 2007 2:56 PM
> To: java-userlucene.apache.org
> Subject: Recreating an index
> 
> *****  This message comes from the Internet Network
*****
> 
> Hello, I have a system that uses lucene to index
information contained
> on text files, one register per line.
> When I start up, I load the text file and create the
index, after that,
> a Timer starts up, and verifies the file's
lastModified() attribute, if
> that changed, I need to recreate the index.
> 
> The problem is, I can't just delete the old index and
create a new one,
> because people are querying it. The idea is to create a
temporary index,
> and when it's done, substitute the old index with the
new one.
> 
> Any tips on doing that ?
> 
> 
> 
> Thanks a lot
> 
> gui
> 
> 
>
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