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From Cheng <zhoucheng2...@gmail.com>
Subject Re: Seem contradictive -- indexwriter in handling multiple threads
Date Wed, 11 Jan 2012 20:53:47 GMT
Will do thanks

On Wed, Jan 11, 2012 at 3:37 PM, Michael McCandless <
lucene@mikemccandless.com> wrote:

> Yes, it's best to share one IndexSearcher/IndexReader across all
> threads... and if you ever find evidence this hurts concurrency then
> please post back :)
>
> Mike McCandless
>
> http://blog.mikemccandless.com
>
> On Wed, Jan 11, 2012 at 3:29 PM, Cheng <zhoucheng2008@gmail.com> wrote:
> > Will do if I see a perf gain.
> >
> > The other issue is that in each thread my apps will not only do indexing
> > but searching. That means I will have to pass through the ram directory
> > instance, along with the writer instance, to every thread so that the
> > searcher can be built on.
> >
> > Should I create a same reader and a same searcher and pass them through
> > every thread too?
> >
> >
> >
> > On Wed, Jan 11, 2012 at 3:21 PM, Michael McCandless <
> > lucene@mikemccandless.com> wrote:
> >
> >> Yes that would work fine.... but you should see a net perf loss by
> >> doing so (once you include time to flush/sync the RAMDir to an FSDir).
> >>
> >> If you see a perf gain then please report back!
> >>
> >> Mike McCandless
> >>
> >> http://blog.mikemccandless.com
> >>
> >> On Wed, Jan 11, 2012 at 3:09 PM, Cheng <zhoucheng2008@gmail.com> wrote:
> >> > Can I create a RAMDirectory based writer and have it work cross all
> >> > threads? In the sense, I would like to use RAMDirectory every where
> and
> >> > have the RAMDirectory written to FSDirectory in the end.
> >> >
> >> > I suppose that should work, right?
> >> >
> >> >
> >> > On Wed, Jan 11, 2012 at 2:31 PM, Michael McCandless <
> >> > lucene@mikemccandless.com> wrote:
> >> >
> >> >> On Wed, Jan 11, 2012 at 1:32 PM, dyzc2010 <zhoucheng2008@gmail.com>
> >> wrote:
> >> >>
> >> >> > Mike, do you mean if I create a FSDirectory based writer in first
> >> place,
> >> >> then the writer should be used in every thread rather than create a
> new
> >> >> RAMDirectory based writer in that thread?
> >> >>
> >> >> Right.
> >> >>
> >> >> > What about I do want to use RAMDirectory to speed up the index
and
> >> >> search processes?
> >> >>
> >> >> IndexWriter is very efficient in using RAM across multiple threads
> >> >> now... so this isn't worth it at indexing time.
> >> >>
> >> >> At search time... MMapDirectory is a good way to let the OS use
> >> >> currently free RAM for caching.
> >> >>
> >> >> Mike McCandless
> >> >>
> >> >> http://blog.mikemccandless.com
> >> >>
> >> >> ---------------------------------------------------------------------
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> >> >>
> >> >>
> >>
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> >>
> >>
>
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