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From "Noble Paul നോബിള്‍ नोब्ळ्" <noble.p...@gmail.com>
Subject Re: Realtime Search for Social Networks Collaboration
Date Sat, 20 Sep 2008 20:04:47 GMT
Moving back to RDBMS model will be a big step backwards where we miss
mulivalued fields and arbitrary fields .

On Tue, Sep 9, 2008 at 4:17 AM, Jason Rutherglen
<jason.rutherglen@gmail.com> wrote:
> Cool.  I mention H2 because it does have some Lucene code in it yes.
> Also according to some benchmarks it's the fastest of the open source
> databases.  I think it's possible to integrate realtime search for H2.
>  I suppose there is no need to store the data in Lucene in this case?
> One loses the multiple values per field Lucene offers, and the schema
> become static.  Perhaps it's a trade off?
>
> On Mon, Sep 8, 2008 at 6:17 PM, J. Delgado <joaquin.delgado@gmail.com> wrote:
>> Yes, both Marcelo and I would be interested.
>>
>> We looked into H2 and it looks like something similar to Oracle's ODCI can
>> be implemented. Plus the primitive full-text implementación is based on
>> Lucene.
>> I say primitive because looking at the code I saw that one cannot define an
>> Analyzer and for each scan corresponding to a where clause a searcher is
>> open and closed, instead of having a pool, plus it does not have any way to
>> queue changes to reduce the use of the IndexWriter, etc.
>>
>> But its open source and that is a great starting point!
>>
>> -- Joaquin
>>
>> On Mon, Sep 8, 2008 at 2:05 PM, Jason Rutherglen
>> <jason.rutherglen@gmail.com> wrote:
>>>
>>> Perhaps an interesting project would be to integrate Ocean with H2
>>> www.h2database.com to take advantage of both models.  I'm not sure how
>>> exactly that would work, but it seems like it would not be too
>>> difficult.  Perhaps this would solve being able to perform faster
>>> hierarchical queries and perhaps other types of queries that Lucene is
>>> not capable of.
>>>
>>> Is this something Joaquin you are interested in collaborating on?  I
>>> am definitely interested in it.
>>>
>>> On Sun, Sep 7, 2008 at 4:04 AM, J. Delgado <joaquin.delgado@gmail.com>
>>> wrote:
>>> > On Sat, Sep 6, 2008 at 1:36 AM, Otis Gospodnetic
>>> > <otis_gospodnetic@yahoo.com> wrote:
>>> >>
>>> >> Regarding real-time search and Solr, my feeling is the focus should
be
>>> >> on
>>> >> first adding real-time search to Lucene, and then we'll figure out how
>>> >> to
>>> >> incorporate that into Solr later.
>>> >
>>> >
>>> > Otis, what do you mean exactly by "adding real-time search to Lucene"?
>>> >  Note
>>> > that Lucene, being a indexing/search library (and not a full blown
>>> > search
>>> > engine), is by definition "real-time": once you add/write a document to
>>> > the
>>> > index it becomes immediately searchable and if a document is logically
>>> > deleted and no longer returned in a search, though physical deletion
>>> > happens
>>> > during an index optimization.
>>> >
>>> > Now, the problem of adding/deleting documents in bulk, as part of a
>>> > transaction and making these documents available for search immediately
>>> > after the transaction is commited sounds more like a search engine
>>> > problem
>>> > (i.e. SOLR, Nutch, Ocean), specially if these transactions are known to
>>> > be
>>> > I/O expensive and thus are usually implemented bached proceeses with
>>> > some
>>> > kind of sync mechanism, which makes them non real-time.
>>> >
>>> > For example, in my previous life, I designed and help implement a
>>> > quasi-realtime enterprise search engine using Lucene, having a set of
>>> > multi-threaded indexers hitting a set of multiple indexes alocatted
>>> > accross
>>> > different search services which powered a broker based distributed
>>> > search
>>> > interface. The most recent documents provided to the indexers were
>>> > always
>>> > added to the smaller in-memory (RAM) indexes which usually could absorbe
>>> > the
>>> > load of a bulk "add" transaction and later would be merged into larger
>>> > disk
>>> > based indexes and then flushed to make them ready to absorbe new fresh
>>> > docs.
>>> > We even had further partitioning of the indexes that reflected time
>>> > periods
>>> > with caps on size for them to be merged into older more archive based
>>> > indexes which were used less (yes the search engine default search was
>>> > on
>>> > data no more than 1 month old, though user could open the time window by
>>> > including archives).
>>> >
>>> > As for SOLR and OCEAN,  I would argue that these semi-structured search
>>> > engines are becomming more and more like relational databases with
>>> > full-text
>>> > search capablities (without the benefit of full reletional algebra --
>>> > for
>>> > example joins are not possible using SOLR). Notice that "real-time" CRUD
>>> > operations and transactionality are core DB concepts adn have been
>>> > studied
>>> > and developed by database communities for aquite long time. There has
>>> > been
>>> > recent efforts on how to effeciently integrate Lucene into releational
>>> > databases (see Lucene JVM ORACLE integration, see
>>> >
>>> > http://marceloochoa.blogspot.com/2007/09/running-lucene-inside-your-oracle-jvm.html)
>>> >
>>> > I think we should seriously look at joining efforts with open-source
>>> > Database engine projects, written in Java (see
>>> > http://java-source.net/open-source/database-engines) in order to blend
>>> > IR
>>> > and ORM for once and for all.
>>> >
>>> > -- Joaquin
>>> >
>>> >
>>> >>
>>> >> I've read Jason's Wiki as well.  Actually, I had to read it a number
of
>>> >> times to understand bits and pieces of it.  I have to admit there is
>>> >> still
>>> >> some fuzziness about the whole things in my head - is "Ocean" something
>>> >> that
>>> >> already works, a separate project on googlecode.com?  I think so.  If
>>> >> so,
>>> >> and if you are working on getting it integrated into Lucene, would it
>>> >> make
>>> >> it less confusing to just refer to it as "real-time search", so there
>>> >> is no
>>> >> confusion?
>>> >>
>>> >> If this is to be initially integrated into Lucene, why are things like
>>> >> replication, crowding/field collapsing, locallucene, name service, tag
>>> >> index, etc. all mentioned there on the Wiki and bundled with
>>> >> description of
>>> >> how real-time search works and is to be implemented?  I suppose
>>> >> mentioning
>>> >> replication kind-of makes sense because the replication approach is
>>> >> closely
>>> >> tied to real-time search - all query nodes need to see index changes
>>> >> fast.
>>> >>  But Lucene itself offers no replication mechanism, so maybe the
>>> >> replication
>>> >> is something to figure out separately, say on the Solr level, later
on
>>> >> "once
>>> >> we get there".  I think even just the essential real-time search
>>> >> requires
>>> >> substantial changes to Lucene (I remember seeing large patches in
>>> >> JIRA),
>>> >> which makes it hard to digest, understand, comment on, and ultimately
>>> >> commit
>>> >> (hence the luke warm response, I think).  Bringing other non-essential
>>> >> elements into discussion at the same time makes it more difficult t
o
>>> >>  process all this new stuff, at least for me.  Am I the only one who
>>> >> finds
>>> >> this hard?
>>> >>
>>> >> That said, it sounds like we have some discussion going (Karl...), so
I
>>> >> look forward to understanding more! :)
>>> >>
>>> >>
>>> >> Otis
>>> >> --
>>> >> Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch
>>> >>
>>> >>
>>> >>
>>> >> ----- Original Message ----
>>> >> > From: Yonik Seeley <yonik@apache.org>
>>> >> > To: java-dev@lucene.apache.org
>>> >> > Sent: Thursday, September 4, 2008 10:13:32 AM
>>> >> > Subject: Re: Realtime Search for Social Networks Collaboration
>>> >> >
>>> >> > On Wed, Sep 3, 2008 at 6:50 PM, Jason Rutherglen
>>> >> > wrote:
>>> >> > > I also think it's got a
>>> >> > > lot of things now which makes integration difficult to do
properly.
>>> >> >
>>> >> > I agree, and that's why the major bump in version number rather
than
>>> >> > minor - we recognize that some features will need some amount of
>>> >> > rearchitecture.
>>> >> >
>>> >> > > I think the problem with integration with SOLR is it was designed
>>> >> > > with
>>> >> > > a different problem set in mind than Ocean, originally the
CNET
>>> >> > > shopping application.
>>> >> >
>>> >> > That was the first use of Solr, but it actually existed before
that
>>> >> > w/o any defined use other than to be a "plan B" alternative to
MySQL
>>> >> > based search servers (that's actually where some of the parameter
>>> >> > names come from... the default /select URL instead of /search,
the
>>> >> > "rows" parameter, etc).
>>> >> >
>>> >> > But you're right... some things like the replication strategy were
>>> >> > designed (well, borrowed from Doug to be exact) with the idea that
it
>>> >> > would be OK to have slightly "stale" views of the data in the range
>>> >> > of
>>> >> > minutes.  It just made things easier/possible at the time.  But
tons
>>> >> > of Solr and Lucene users want almost instantaneous visibility of
>>> >> > added
>>> >> > documents, if they can get it.  It's hardly restricted to social
>>> >> > network applications.
>>> >> >
>>> >> > Bottom line is that Solr aims to be a general enterprise search
>>> >> > platform, and getting as real-time as we can get, and as scalable
as
>>> >> > we can get are some of the top priorities going forward.
>>> >> >
>>> >> > -Yonik
>>> >> >
>>> >> > ---------------------------------------------------------------------
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>>> >>
>>> >>
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>>> >>
>>> >
>>> >
>>>
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>>>
>>
>>
>
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>
>



-- 
--Noble Paul

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