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From Ravikumar Govindarajan <ravikumar.govindara...@gmail.com>
Subject Re: Incremental Field Updates
Date Thu, 03 Jul 2014 10:22:57 GMT
In case of sorting, updatable DocValues may be what you are looking for.

But updatable fields for searching is a different beast.

A sample approach is documented at
http://www.flax.co.uk/blog/2012/06/22/updating-individual-fields-in-lucene-with-a-redis-backed-codec/

The general problems with updatable postings-list AFAIK are

1. Impossible to correctly score updated documents
2. Segment Merges could miss out updates
3. Might behave in-correctly with NRT
4. Freq updates could end-up creating lots of files because of append-only
    nature of lucene...

May be if you are not too worried about scoring, correct NRT behavior etc
you can attempt a solution like the RedisCodec stuff...

Segregating static & dynamic fields into 2 separate indexes as described
here
http://www.lucenerevolution.org/2013/Sidecar-Index-Solr-Components-for-Parallel-Index-Management
may be of some use to you

--
Ravi



On Wed, Jul 2, 2014 at 7:29 PM, Shai Erera <serera@gmail.com> wrote:

> Using BinaryDocValues is not recommended for all scenarios. It is a
> "catchall" alternative to the other DocValues types. I would not use it
> unless it makes sense for your application, even if it means that you need
> to re-index a document in order to update a single field.
>
> DocValues are not good for "search" - by search I assume you mean take a
> query such as "apache AND lucene" and find all documents which contain both
> terms under the same field. They are good for sorting and faceting though.
>
> So I guess the answer to your question is "it depends" (it always is!) - I
> would use DocValues for sorting and faceting, but not for regular search
> queries. And I would use BinaryDocValues only when the other DocValues
> types don't match.
>
> Also, note that the current field-level update of DocValues is not always
> better than re-indexing the document, you can read here for more details:
> http://shaierera.blogspot.com/2014/04/benchmarking-updatable-docvalues.html
>
> Shai
>
>
> On Tue, Jul 1, 2014 at 9:17 PM, Sandeep Khanzode <
> sandeep_khanzode@yahoo.com.invalid> wrote:
>
> > Hi Shai,
> >
> > So one follow-up question.
> >
> > Assume that my use case is to have approx. ~50M documents indexed with
> > each document having about ~10-15 indexed but not stored fields. These
> > fields will never change, but there are another ~5-6 fields that will
> > change and will continue to change after the index is written. These ~5-6
> > fields may also be multivalued. The size of this index turns out to be
> > ~120GB.
> >
> > In this case, I would like to sort or facet or search on these ~5-6
> > fields. Which approach do you suggest? Should I use BinaryDocValues and
> > update using IW or use either a ParallelReader/Join query.
> >
> > -----------------------
> > Thanks n Regards,
> > Sandeep Ramesh Khanzode
> >
> >
> > On Tuesday, July 1, 2014 9:53 PM, Shai Erera <serera@gmail.com> wrote:
> >
> >
> >
> > Except that Lucene now offers efficient numeric and binary DocValues
> > updates. See IndexWriter.updateNumeric/Binary...
> >
> > On Jul 1, 2014 5:51 PM, "Erick Erickson" <erickerickson@gmail.com>
> wrote:
> >
> > > This JIRA is "complicated", don't really expect it in 4.9 as it's
> > > been hanging around for quite a while. Everyone would like this,
> > > but it's not easy.
> > >
> > > Atomic updates will work, but you have to stored="true" for all
> > > source fields. Under the covers this actually reads the document
> > > out of the stored fields, deletes the old one and adds it
> > > over again.
> > >
> > > FWIW,
> > > Erick
> > >
> > > On Tue, Jul 1, 2014 at 5:32 AM, Sandeep Khanzode
> > > <sandeep_khanzode@yahoo.com.invalid> wrote:
> > > > Hi,
> > > >
> > > > I wanted to know of the best approach to follow if a few fields in my
> > > indexed documents are changing at run time (after index and before or
> > > during search), but a majority of them are created at index time.
> > > >
> > > > I could see the JIRA given below but it is scheduled for Lucene 4.9,
> I
> > > believe.
> > > >
> > > > There are a few other approaches, like maintaining a separate index
> for
> > > changing fields and use either a parallelreader or use a Join.
> > > >
> > > > Can everyone share their experience for this scenario on how it is
> > > handled in your systems? Thanks,
> > > >
> > > > [LUCENE-4258] Incremental Field Updates through Stacked Segments -
> ASF
> > > JIRA
> > > >
> > > >
> > > >  [LUCENE-4258] Incremental Field Updates through Stacked Segments -
> ASF
> > > JIRA
> > > > Shai and I would like to start working on the proposal to Incremental
> > > Field Updates outlined here (
> > http://markmail.org/message/zhrdxxpfk6qvdaex
> > > ).
> > > > View on issues.apache.org Preview by Yahoo
> > > >
> > > >
> > > > -----------------------
> > > > Thanks n Regards,
> > > > Sandeep Ramesh Khanzode
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> > > For additional commands, e-mail: java-user-help@lucene.apache.org
> > >
> > >
>

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