No! It's not like this in my code. This code opens an IndexReader every time
I call newIndexSearcher().
In my code it is sometime like -
IndexReader[] irs;
// irs is a global array containing IndexReaders which are opened when the
application starts
.....
.....
IndexSearcher[] getIndexSearchers(IndexReader[] irs)
{
IndexSearcher[] iss = new IndexSearcher[irs.length];
for(int i=0;i<irs.length;i++)
{
iss[i] = new IndexSearcher(irs[i]);
iss[i].setSimilarity(new MySimilarity(new
String[]{"contents"}));
}
return iss;
}
ParallelMultiSearcher getParallelMultiSearcher(<country and time related
parameters>) throws IOException
{
// by checking country and time related parameters, correct elements
are chosen from complete array of IndexReaders (irs) to pass in the function
for(int i=0;i<irs.length;i++)
{
if(<country and time related parameters match for current
value of "i">)
{
return (new
ParallelMultiSearcher(getIndexSearchers((IndexReader[])irs[i])));
}
}
// ideally this code should never be executed
return (new
ParallelMultiSearcher(getIndexSearchers(prepareReaders(<country
and time related parameters>))));
}
2010/4/24 Ivan Liu <[email protected]>
> 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
>
> my blog:冲浪板 <http://chonglangban.appspot.com/>
> my site:Keji Technology <http://kejiblog.appspot.com/>
>
--
Regards,
Samar
