Well, it's sort of documented on IndexWriterConfig already:
* Once {@link IndexWriter} has been created with this object, changes to
this
* object will not affect the {@link IndexWriter} instance. For that, use
* {@link LiveIndexWriterConfig} that is returned from {@link
IndexWriter#getConfig()}.
And also on IndexWriter ctor:
* Note that the passed in {@link IndexWriterConfig} is
* privately cloned, which, in-turn, clones the
* {@link IndexWriterConfig#getFlushPolicy() flush policy},
* {@link IndexWriterConfig#getIndexDeletionPolicy() deletion policy},
* {@link IndexWriterConfig#getMergePolicy() merge policy},
* and {@link IndexWriterConfig#getMergeScheduler() merge scheduler}.
* If you need to make subsequent "live"
* changes to the configuration use {@link #getConfig}.
So I don't think more documentation will help clarify what's going on.
If we need to do anything (and I'm not sure we should!), it's probably to
avoid cloning what's not needed.
But I'm not sure ... maybe someone has an IndexDeletionPolicy which needs
to be cloned for safetyness...
Shai
On Thu, Jul 25, 2013 at 10:15 PM, Marcos Juarez Lopez <mjua...@gmail.com>wrote:
> Shai and Michael,
>
> Thanks for your help. That did the trick, getting the live
> IndexDeletionPolicy from the live writer config.
>
> I also agree with Michael, it's not obvious at all from the docs and/or
> Lucene in Action book. Maybe this can be clarified on the
> IndexDeletionPolicy javadocs going forward?
>
> Thanks,
>
> Marcos Juarez
>
>
>
> On Wed, Jul 24, 2013 at 5:33 AM, Michael McCandless <
> luc...@mikemccandless.com> wrote:
>
> > This is unfortunately very trappy ... this happened with LUCENE-4876,
> > where we added cloning of IndexDeletionPolicy on IW construction.
> > It's very confusing that the IDP you set on your IWC is not in fact
> > the one that IW uses...
> >
> > Mike McCandless
> >
> > http://blog.mikemccandless.com
> >
> >
> > On Wed, Jul 24, 2013 at 2:35 AM, Shai Erera <ser...@gmail.com> wrote:
> > > Hi
> > >
> > > In Lucene 4.4 we've improved the snapshotting process so that you don't
> > > need to specify an ID.
> > > Also, there's a new Replicator module which can be used for just that
> > > purpose - take hot index backups of the index.
> > > It pretty much hides most of the snapshotting from you. You can read
> > about
> > > it here: http://shaierera.blogspot.com/2013/05/the-replicator.html
> > >
> > > As for your problem, I think it's related to the fact IndexWriter
> clones
> > > the given IndexWriterConfig, including the SnapshotDeletionPolicy.
> > > So you should obtain it from
> IW.getLiveConfig().getIndexDeletionPolicy(),
> > > rather than IndexWriterConfig.getIndexDeletionPolicy(). I'm not sure
> what
> > > Indexer.getSnapshotter() does, but I'd make sure that it uses IW.
> > >
> > > Shai
> > >
> > >
> > > On Wed, Jul 24, 2013 at 7:34 AM, Marcos Juarez Lopez <
> mjua...@gmail.com
> > >wrote:
> > >
> > >> I'm trying to get Lucene's hot backup functionality to work. I posted
> > the
> > >> question in detail over at StackOverflow, but it seems there's very
> > little
> > >> Lucene knowledge over there.
> > >>
> > >> Basically, I think I have setup everything correctly, but I can't get
> a
> > >> valid snapshot when trying to do a backup. I'm following both the
> > Lucene
> > >> book's instructions, as well as the latest Lucene Javadocs, to no
> avail.
> > >> Original question at the link, but I'll copy the relevant bits below:
> > >>
> > >>
> http://stackoverflow.com/questions/17753226/lucene-4-3-1-backup-process
> > >>
> > >> This is the code I have up to now:
> > >>
> > >> public Indexer(Directory indexDir, PrintStream printStream) throws
> > >> IOException {
> > >> IndexWriterConfig config = new
> > >> IndexWriterConfig(Version.LUCENE_43, new Analyzer());
> > >> snapshotter = new SnapshotDeletionPolicy(new
> > >> KeepOnlyLastCommitDeletionPolicy());
> > >> writerConfig.setIndexDeletionPolicy(snapshotter);
> > >> indexWriter = new IndexWriter(indexDir, writerConfig);
> > >> }
> > >>
> > >> And when starting the backup, you can't just do
> snapshotter.snapshot().
> > You
> > >> now have to specify an arbitrary commitIdentifier id, and use that
> after
> > >> you're done to release the snapshot.
> > >>
> > >> SnapshotDeletionPolicy snapshotter = indexer.getSnapshotter();
> > >> String commitIdentifier = generateCommitIdentifier();
> > >> try {
> > >> IndexCommit commit = snapshotter.snapshot(commitIdentifier);
> > >> for (String fileName : commit.getFileNames()) {
> > >> backupFile(fileName);
> > >> }
> > >> } catch (Exception e) {
> > >> logger.error("Exception", e);
> > >> } finally {
> > >> snapshotter.release(commitIdentifier);
> > >> indexer.deleteUnusedFiles();
> > >> }
> > >>
> > >> However, this doesn't seem to be working. Regardless of whether there
> > have
> > >> been docs indexed or not, and regardless of whether I have committed
> or
> > >> not, my call tosnapshotter.snapshot(commitIdentifier) always throws an
> > >> IllegalStateException sayingNo index commit to snapshot. Looking at
> the
> > >> code, the SnapshotDeletionPolicy seems to think there have been no
> > commits,
> > >> even though I'm committing to disk every 5 seconds or so. I've
> verified,
> > >> and there are docs being written and committed to indexes all the
> time,
> > but
> > >> snapshotter always thinks there have been zero commits.
> > >>
> > >> Any idea of what I'm doing wrong?
> > >>
> > >> Thanks!
> > >>
> > >> Marcos Juarez
> > >>
> >
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>
