Thanks for your replies. However, in my scenario, an external backup utility would be used to take backup of the Lucene index. I just need to ensure that index do not get changed when a search is performed over it or due to internal Lucene housekeeping/optimization/merge activities.
Ashish -----Original Message----- From: Michael McCandless [mailto:[email protected]] Sent: Wednesday, April 17, 2013 4:55 PM To: [email protected] Subject: Re: Taking backup of a Lucene index On Wed, Apr 17, 2013 at 7:02 AM, Thomas Matthijs <[email protected]> wrote: > On Wed, Apr 17, 2013 at 12:57 PM, Ashish Sarna <[email protected]>wrote: > >> I want to take back-up of a Lucene index. I need to ensure that index files >> would not change when I take their backup. >> > > >> >> I am concerned about the housekeeping/merge/optimization activities which >> Lucene performs internally. I am not sure when/how these activities are >> performed by Lucene and how we can prevent them. >> >> > > Use a > http://lucene.apache.org/core/4_2_1/core/org/apache/lucene/index/SnapshotDel etionPolicy.html > Take a snapshot, backup/copy all the files in the commit, relase the > snapshot That's right! Because Lucen is "write-once" (each file is opened, written, and never changed, and no file is over-written), the SnapshotDeletionPolicy let's you take a hot (live) point-in-time backup even while IndexWriter continues making changes to the index. As long as you hold that snapshot, all files it references will not be deleted, just be sure to release it once you're done backing up. Mike McCandless http://blog.mikemccandless.com --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
