dhis2-devs team mailing list archive

[Jason Pickering <jason.p.pickering@xxxxxxxxx>]

While on the subject of different db paradigms, I have been playing
around with LucidDB, a column based DB, which theoretically should be
more efficient for data warehousing operations than a transactional DB
like Postgres or MySQL. I have not managed to get it to work yet
(there is a Postgresql connector which seems to present LucidDB as a
Postgresql DB). I think for data warehousing applications, and even
potentially for day-to-day operations, the penalty of writing
inserting data into the DB (which transactional DBs are designed for)
may outweigh the performance enhancements that column based DBs (such
as Lucid) are designed for. If we could speed up analysis operations
(such as the data mart) and maybe live with some penalties of
inserting data (such as data entry, which for any DB is almost nothing
in most DHIS2 use cases) it might be a solid contender for certain
situations. Of course, the current data mart operations relies of the
insertion of a large amount of data into a cross tabulation table, so
I doubt that things will work as they are in the current data mart
implementation. In all likelihood, an ETL step would be required to
get data out of the transactional DB and into the columnar DB, which
is pretty normal for data warehouse operations, to see any potential
performance enhancements.

 Anyway, something to consider.

On Thu, May 20, 2010 at 8:52 PM, Bob Jolliffe <bobjolliffe@xxxxxxxxx> wrote:
> While on the subject of different db paradigms, there is also apache
> jackrabbit which is better suited for the storage of tree like
> structures (particularly xml) than traditional rdbms.  There are a
> number of things which we currently store on the file system in the
> conf directory for example.  There is also a need to persist xml
> documents such as xslts, dxf metadata snapshots and even possibly
> xforms and svg graphs.  jackrabbit provides a nice standards compliant
> way to do these things (see first hops) and can persist behind the
> scenes to mysql, h2, postgres and others.  In that sense its not
> really so much a replacement for rdbm as a content oriented interface.
>  Because jackrabbit is really a content repository implementation it
> can persist any kind of content, including pictures of flags, pdfs
> etc.  In terms of a metadata repository it is really well suited for
> managing trees of xml documents and has versioning builtin which is
> kind of important for metadata.
>
> Regards
> Bob
>
> On 20 May 2010 19:09, Knut Staring <knutst@xxxxxxxxx> wrote:
>> Don't know much about it, but doesn't seem targeted at applications
>> heavy with numerical data? The JSON focus should go well with
>> Javascript GUIs, I guess.
>>
>> "MongoDB is designed for problems without heavy transactional
>> requirements that aren't easily solved by traditional RDBMSs,
>> including problems that require databases to span many servers.
>> Like other document-oriented database systems such as CouchDB, MongoDB
>> is not a relational database management system. The database manages
>> collections of JSON-like documents that are stored in a binary format
>> referred to as BSON."
>>
>> http://en.wikipedia.org/wiki/MongoDB
>>
>> On Thu, May 20, 2010 at 8:00 PM, Ngoc Thanh Nguyen
>> <thanh.hispvietnam@xxxxxxxxx> wrote:
>>> That sounds interesting. No database, no table, or hibernate mapping. Fast
>>> query, high performance. What we want more?
>>>
>>> http://www.mongodb.org/display/DOCS/Java+Tutorial
>>>
>>> Anyone have ideas about this?
>>>
>>> Thanh
>>>
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>>>
>>
>>
>>
>> --
>> Cheers,
>> Knut Staring
>>
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>
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-- 
--
Jason P. Pickering
email: jason.p.pickering@xxxxxxxxx
tel:+260968395190