like this?
public synchronized IndexSearcher newIndexSearcher() {
try {
// semaphore.acquire();
if (null == indexSearcher) {
Directory directory = FSDirectory.open(new
File(Config.DB_DIR+"/rssindex"));
indexSearcher = new IndexSearcher(IndexReader.open(directory, true));
} else {
IndexReader indexReader = indexSearcher.getIndexReader();
IndexReader newIndexReader = indexReader.reopen();
if (newIndexReader!=indexReader) {
indexReader.close();
indexSearcher.close();
indexSearcher = new IndexSearcher(newIndexReader);
}
}
return indexSearcher;
} catch (CorruptIndexException e) {
log.error(e.getMessage(),e);
return null;
} catch (IOException e) {
log.error(e.getMessage(),e);
return null;
}finally{
// semaphore.release();
}
}
2010/4/22 Samarendra Pratap <[email protected]>
> Thanks Mike.
> That solved a query which was itching my mind for a long time.
>
> On Thu, Apr 22, 2010 at 4:41 PM, Michael McCandless <
> [email protected]> wrote:
>
> > It's the IndexReader that's costly to open/warm, so ideally it should
> > be opened once and shared.
> >
> > The Searchers do very little on construction so re-creating per query
> > should be OK.
> >
> > Mike
> >
> > On Thu, Apr 22, 2010 at 6:38 AM, Samarendra Pratap <[email protected]>
> > wrote:
> > > Greetings to all.
> > > I have read at so many places that we should not open a Searcher for
> > each
> > > request for the sake of performance, but I have always been wondering
> > > whether it is actually Searcher or Reader?
> > >
> > > I have a group of index amounting to 23G which actually contains of
> > > different index directories. The structure is something like following
> > >
> > > Main directory
> > > |
> > > |_________ country1
> > > | |___ country1-time1 (actual index)
> > > | |___ country1-time2 (actual index)
> > > | |___ country1-time3 (actual index)
> > > |
> > > |_________ country2
> > > |___ country2-time1 (actual index)
> > > |___ country2-time2 (actual index)
> > > |___ country2-time3 (actual index)
> > >
> > > When application starts I open IndexReaders on all of actual index
> > > directories (country1-time1, country1-tim2, .... country2-time3) and
> keep
> > > them in a pool.
> > >
> > > At the time of search, IndexSearchers are created by selecting the
> > > appropriate IndexReaders from the pool. These IndexSearchers in turn
> are
> > > used to create a ParallelMultiSearcher. Constructors of IndexSearcher
> and
> > > ParallelMultiSearcher are run for every request.
> > >
> > > Now I believe that creating a pool of ParallelMultiSearcher itself is
> a
> > > good idea but* I wanted to know if reopening **IndexSearchers** will
> > really
> > > degrade performance irrespective of **IndexReaders** being opened
> once*.
> > >
> > > In my performance tests (which may not be very comprehensive) I didn't
> > find
> > > any noticeable difference.
> > >
> > > Please throw some light.
> > >
> > >
> > > --
> > > Regards,
> > > Samar
> > >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: [email protected]
> > For additional commands, e-mail: [email protected]
> >
> >
>
>
> --
> Regards,
> Samar
>
--
冲浪板
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