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https://issues.apache.org/jira/browse/LUCENE-724?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12527500
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Marcelo F. Ochoa commented on LUCENE-724:
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Joaquin at lucene-java-dev wrote:
I'm very happy to announce the partial rework and extension to LUCENE-724
(Oracle-Lucene Integration), primarily based on new requirements from
LendingClub.com, who commissioned the work to Marcelo Ochoa, the contributer of
the original patch (great job Marcelo!). As contribution of LendingClub.com to
the Lucene community we have posted the code on a public CVS (sourceforge) as
explained below.
Here at Lending Club ( www.lendingclub.com) we have very specific needs
regarding the indexing of both structured and unstructured data, most of it
transactional in nature and siting in our Oracle !0gR2 DB, with a highly
complex schema. Our "ranking" of loans in the inventory includes components of
exact, textual and hardcore mathematical calculations including time, amount
and spatial constraints. This integration of Lucene into Oracle as a Domain
Index will now allow us to query this inventory in real-time. Going against the
Lucene index, created on "synthetic documents" comprised of fields being
populated from diverse tables (user data store), eliminates the need to create
very complex joins to link data from different tables at query time. This,
along with the support of the full Lucene query language, makes this a great
alternative to:
1. Using Lucene outside the database which requires "crawling" the data and
storing the index outside the database, loosing all the benefits of a fully
transactional system and a secure environment.
2. Using Oracle Text, which is very powerful but lacks the extensibility and
flexibility that Lucene offers (for example, being able to query directly the
index from the Java layer or implementing our our ranking algorithm), though to
be completely fair some of it is addressed in the new Oracle DB 11g version.
If anyone is interested in learning more how we are going to use this within
Lending Club, please drop me a line. BTW, please make sure you check us out:
"Lending Club ( http://www.lendingclub.com/), the rapidly growing
people-to-people (P2P) lending service that launched as a Facebook application
in May 2007, today announced the public availability of its services with the
launch of LendingClub.com. Lending Club connects lenders and borrowers based
upon shared affinities, enabling them to bypass banks to secure better interest
rates on loans"... more about the announcement here
http://www.sys-con.com/read/428678.htm. We have seen man entrepreneurs applying
for loans and being helped by regular people to build their business with the
money obtained at very low interest.
OK, without further marketing stuff (sorry for that), here is the original note
sent to me by Marcelo that summarizes all the new cool functionalities:
OJVMDirectory, a Lucene Integration running inside the Oracle JVM is going one
step further.
This new release includes:
* Synchronized with latest Lucene 2.2.0 production
* Replaced in memory storage using Vector based implementation by direct
BLOB IO, reducing memory usage for large index.
* Support for user data stores, it means you can not only index one column
at time (limited by Data Cartridge API on 10g), now you can index multiples
columns at base table and columns on related tabled joined together.
* User Data Stores can be customized by the user, it means writing a simple
Java Class users can control which column are indexed, padding
* used or any other functionality previous to document adding step.
* There is a DefaultUserDataStore which gets all columns of the query and
built a Lucene Document with Fields representing each database
* columns these fields are automatically padded if they have NUMBER or
rounded if they have DATE data, for example.
* lcontains() SQL operator support full Lucene's QueryParser syntax to
provide access to all columns indexed, see examples below.
* Support for DOMAIN_INDEX_SORT and FIRST_ROWS hint, it means that if you
want to get rows order by lscore() operator (ascending,descending) the
optimizer hint will assume that Lucene Domain Index will returns rowids in
proper order avoided an inline-view to sort it.
* Automatic index synchronization by using AQ's Call Back.
* Lucene Domain Index creates extra tables named IndexName$T and an Oracle
AQ named IndexName$Q with his storage table IndexName$QT at user's schema, so
you can alter storage's preference if you want.
* ojvm project is at SourceForge.net CVS, so anybody can get it and
collaborate ;)
* Tested against 10gR2 and 11g database.
Some sample usages:
create table t2 (
f4 number primary key,
f5 VARCHAR2(200));
create table t1 (
f1 number,
f2 CLOB,
f3 number,
CONSTRAINT t1_t2_fk FOREIGN KEY (f3)
REFERENCES t2(f4) ON DELETE cascade);
create index it1 on t1(f3) indextype is lucene.LuceneIndex
parameters('Analyzer:org.apache.lucene.analysis
.SimpleAnalyzer;ExtraCols:f2');
alter index it1
parameters('ExtraCols:f2,t2.f5;ExtraTabs:t2;WhereCondition:t1.f3=t2.f4;DecimalFormat:000');
Lucene domain index will store f2 and f3 columns of table t1 plus f5 of table
t2.
So you can query then with:
select lscore(1),f2 from t1 where lcontains(f3, 'f2:test',1) > 0;
or
select lscore(1),f2 from t1 where lcontains(f3, 'f2:test and f3:[001 to
200]',1) > 0;
select /*+ DOMAIN_INDEX_SORT */ lscore(1),f2,t2.f5
from t1,t2
where lcontains(f3, 'f2:test1 and f3:[001 to 200] and t2.f5:test2',1) > 0
and t1.f3=t2.f4
order by lscore(1) asc;
In latest example Oracle's optimizer will assume that Lucene Domain Index will
resolve first a set of rowid matching "f2:test1 and f3:[001 to 200] and
t2.f5:test2" then will direct access by by index rowid on table t1 and perform
the join with t2.
More examples and information can be found at:
http://dbprism.cvs.sourceforge.net/dbprism/ojvm/Readme.txt?revision=1.10&view=markup
> Oracle JVM implementation for Lucene DataStore also a preliminary
> implementation for an Oracle Domain index using Lucene
> ------------------------------------------------------------------------------------------------------------------------
>
> Key: LUCENE-724
> URL: https://issues.apache.org/jira/browse/LUCENE-724
> Project: Lucene - Java
> Issue Type: New Feature
> Components: Store
> Affects Versions: 2.0.0
> Environment: Oracle 10g R2 with latest patchset, there is a txt file
> into the lib directory with the required libraries to compile this extension,
> which for legal issues I can't redistribute. All these libraries are include
> into the Oracle home directory,
> Reporter: Marcelo F. Ochoa
> Priority: Minor
> Attachments: ojvm-01-09-07.tar.gz, ojvm-11-28-06.tar.gz,
> ojvm-12-20-06.tar.gz, ojvm.tar.gz
>
>
> Here a preliminary implementation of the Oracle JVM Directory data store
> which replace a file system by BLOB data storage.
> The reason to do this is:
> - Using traditional File System for storing the inverted index is not a
> good option for some users.
> - Using BLOB for storing the inverted index running Lucene outside the
> Oracle database has a bad performance because there are a lot of network
> round trips and data marshalling.
> - Indexing relational data stores such as tables with VARCHAR2, CLOB or
> XMLType with Lucene running outside the database has the same problem as the
> previous point.
> - The JVM included inside the Oracle database can scale up to 10.000+
> concurrent threads without memory leaks or deadlock and all the operation on
> tables are in the same memory space!!
> With these points in mind, I uploaded the complete Lucene framework inside
> the Oracle JVM and I runned the complete JUnit test case successful, except
> for some test such as the RMI test which requires special grants to open
> ports inside the database.
> The Lucene's test cases run faster inside the Oracle database (11g) than
> the Sun JDK 1.5, because the classes are automatically JITed after some
> executions.
> I had implemented and OJVMDirectory Lucene Store which replaces the file
> system storage with a BLOB based storage, compared with a RAMDirectory
> implementation is a bit slower but we gets all the benefits of the BLOB
> storage (backup, concurrence control, and so on).
> The OJVMDirectory is cloned from the source at
> http://issues.apache.org/jira/browse/LUCENE-150 (DBDirectory) but with some
> changes to run faster inside the Oracle JVM.
> At this moment, I am working in a full integration with the SQL Engine using
> the Data Cartridge API, it means using Lucene as a new Oracle Domain Index.
> With this extension we can create a Lucene Inverted index in a table using:
> create index it1 on t1(f2) indextype is LuceneIndex parameters('test');
> assuming that the table t1 has a column f2 of type VARCHAR2, CLOB or
> XMLType, after this, the query against the Lucene inverted index can be made
> using a new Oracle operator:
> select * from t1 where contains(f2, 'Marcelo') = 1;
> the important point here is that this query is integrated with the execution
> plan of the Oracle database, so in this simple example the Oracle optimizer
> see that the column "f2" is indexed with the Lucene Domain index, then using
> the Data Cartridge API a Java code running inside the Oracle JVM is executed
> to open the search, a fetch all the ROWID that match with "Marcelo" and get
> the rows using the pointer,
> here the output:
> SELECT STATEMENT ALL_ROWS 3 1
> 115
> TABLE ACCESS(BY INDEX ROWID) LUCENE.T1 3 1 115
> DOMAIN INDEX LUCENE.IT1
> Another benefits of using the Data Cartridge API is that if the table T1 has
> insert, update or delete rows operations a corresponding Java method will be
> called to automatically update the Lucene Index.
> There is a simple HTML file with some explanation of the code.
> The install.sql script is not fully tested and must be lunched into the
> Oracle database, not remotely.
> Best regards, Marcelo.
> - For Oracle users the big question is, Why do I use Lucene instead of Oracle
> Text which is implemented in C?
> I think that the answer is too simple, Lucene is open source and anybody
> can extend it and add the functionality needed
> - For Lucene users which try to use Lucene as enterprise search engine, the
> Oracle JVM provides an highly scalable container which can scale up to
> 10.000+ concurrent session and with the facility of querying table in the
> same memory space.
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