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From "Jason Rutherglen" <jason.rutherg...@gmail.com>
Subject Re: SegmentReader with custom setting of deletedDocs, single reusable FieldsReader
Date Sun, 29 Jun 2008 17:44:20 GMT
I voted for http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6265734 about
pread not working on Windows.  After thinking more about the pool of
RandomAccessFiles I think
LUCENE-753<https://issues.apache.org/jira/browse/LUCENE-753>is the
best solution.  I am not sure how much work nor if pool of
RandomAccessFiles creates more synchronization problems and if it is only to
benefit windows, does not seem worthwhile.

Seems like LUCENE-753 needs the conditional part on the OS and it can be
committed.

On Sun, Jun 29, 2008 at 10:47 AM, Yonik Seeley <yonik@apache.org> wrote:

> On Sun, Jun 29, 2008 at 9:42 AM, Jason Rutherglen
> <jason.rutherglen@gmail.com> wrote:
> > IndexReader.document as it is is really a lame duck.  The
> > IndexReader.document call being synchronized at the top level drags down
> the
> > performance of systems that store data in Lucene.  A single file
> descriptor
> > for all threads on an index that is constantly returning results with
> fields
> > is a serious problem.  Users are always complaining about this issue and
> now
> > I know why.
>
> Each part of the index (e.g. tis, frq) is actually only covered by a
> single file descriptor by default - stored fields aren't unique in
> that regard.
>
> It's probably the case that the stored fields of a given document are
> much less likely to be in OS cache though... and in that case having
> multiple requests in-flight to the disk could improve things.
>
> On anything except Windows, using pread may be the answer (after the
> other synchronization is also removed of course):
> https://issues.apache.org/jira/browse/LUCENE-753
>
> -Yonik
>
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