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From Rob Bygrave <robin.bygr...@gmail.com>
Subject Re: ParallelReader
Date Fri, 15 Oct 2010 01:42:38 GMT
>> Any case where it would break?

If a query uses multiple fields it would break. That is, usually all the
fields need to be in doc in index 2 - not just the modified one.


On Fri, Oct 15, 2010 at 2:35 PM, Erick Erickson <erickerickson@gmail.com>wrote:

> This seems like far too much work if I'm reading things right. You can't
> update
> a field, but you #can# update a document which actually re-index that
> document
> under the covers (you have to have a way to uniquely identify the doc).
> Then, when
> you reopen your index reader, you'll only see the new value for the one
> field that's
> different. This doesn't rely on any second index at all.
>
> So is there something I'm missing here that caused you to take the route
> you're
> taking? Because I'd just try updating the document and reopening the reader
> first...
>
> HTH
> Erick
>
> On Thu, Oct 14, 2010 at 9:06 PM, Nilesh Vijaywargiay <
> nilesh.vijay@gmail.com
> > wrote:
>
> > Hey Erick, Sure.
> > *
> > *
> > *What I am trying to achieve:*
> >
> > A) Update a field in Index A
> > B) When searching for that old field, it should be a miss.
> >
> > *How I achieved it*
> >
> > *Index 1 *
> > Doc 1 - Field1, Value 1
> > Doc 2 - Field1, Value 1
> >
> > *Index 2*
> > Doc 1 - Field1, Modified_Value 1
> > Doc 2 - EMPTY
> >
> > Add index 2 before Index 1 in the parallel reader.
> > In short, I am creating a new index with same number of documents but all
> > the documents are empty except the ones I want to update.
> >
> > *RESULTS:*
> > If I search for Field1:Value1, I get a miss[What I wanted]
> > If I search for Field1:Modified_Value 1, I get a hit[What I wanted]
> >
> > *PROBLEM*
> > I am kinda finding it surprising that I am able to update a field[I was
> > told
> > I can't]. Ofcourse there is downside of creating a new index with dummy
> > documents which might be huge. But apart from that, Is there something
> > fishy
> > about it? Any case where it would break?
> >
> >
> >
> > On Thu, Oct 14, 2010 at 5:55 PM, Erick Erickson <erickerickson@gmail.com
> > >wrote:
> >
> > > No. And you don't even want to try... Document IDs are NOT invariant.
> > > Particularly
> > > when you delete a document and optimize an index, all the documents
> that
> > > come
> > > after the deleted one get new doc IDs. Trying to keep these two indexes
> > in
> > > synch
> > > will be a nightmare.
> > >
> > > Perhaps you could explain what you're trying to accomplish and we could
> > > suggest
> > > other approaches. See:
> > >
> > > http://people.apache.org/~hossman/#xyproblem<http://people.apache.org/%7Ehossman/#xyproblem>
> > >
> > > Your question appears to be an "XY Problem" ... that is: you are
> dealing
> > > with "X", you are assuming "Y" will help you, and you are asking about
> > "Y"
> > > without giving more details about the "X" so that we can understand the
> > > full issue.  Perhaps the best solution doesn't involve "Y" at all?
> > > See Also: http://www.perlmonks.org/index.pl?node_id=542341
> > >
> > > Best,
> > > Erick
> > >
> > > On Thu, Oct 14, 2010 at 11:42 AM, Nilesh Vijaywargiay <
> > > nilesh.vijay@gmail.com> wrote:
> > >
> > > > I have two index, A and B. Can two documents doc1[in index A] and
> > doc2[in
> > > > index B] have a common field? doc1 and doc2 have same document Id's.
> > > >
> > >
> >
>

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