Andy Seaborne wrote:
>
> It seems to use a non-normalized table design (as did the CStore paper)
> and rely on indexing. It would be interesting to see how that compares
> with a normalized design, which is what most RDF stores use. When
> normalized, the joins for patterns are on fixed size numbers, not string
> comparisons, and don't use secondary indexes (and at least one uses
> bitmap indexes).
>
> SDB is built around a normalized design, and portable across various
> different SQL DBs. The main triple table (or quad table) is 3 columns
> of 4 or 8 bytes (depending on hash vs index allocation of internal ids).
> That means the main table is a thin, long table.
>
> If you want a deep integration of SPARQL and MonetDB, the first thing to
> consider, if pure speed is the objective, is what schema design is best
> for MonetDB.
>
> The reported tests are on a dataset of 50 million triples which is
^
not
> particularly big - it means RAM caching is going to play a significant
> role nowadays (they only used a one-CPU, 4G machine).
> Andy
>
>
> On 01/09/11 19:49, nat lu wrote:
>> Speed I think ! At least in some use cases. (But Im no MonetDB expert)
>> Heres an interesting article that tries a few of them out with MonetDB
>> and CStore.
>>
>> http://oai.cwi.nl/oai/asset/13806/13806B.pdf
>>
>>
>> Whats missing I believe is a the SPARQL endpoint integration.
>>
>> On 01/09/11 08:36, Andy Seaborne wrote:
>>> Tobias,
>>>
>>> To turn the question round - what unique features of MonetDB could be
>>> exposed through SDB to yield a better RDf store?
>>>
>>> The current design covers the current set of databases supported but
>>> it's not fixed - maybe there is something especially useful in MonetDB
>>> and maybe it needs an extension to the design. The design is based on
>>> templating via all those classes (the instance for each database is a
>>> small class). The SQL generator usually needs some per-DB work because
>>> SQL databases aren't exactly very "standard".
>>>
>>> Andy
>>>
>>> On 25/08/11 21:28, Paolo Castagna wrote:
>>>> Hi Tobias,
>>>> first of all, welcome on jena-users mailing list.
>>>>
>>>> Tobias Willig wrote:
>>>>> Hi everyone,
>>>>>
>>>>> I like to add support for MonetDB in SDB and I have two questions
>>>>> concerning
>>>>> this project:
>>>>>
>>>>> 1. How much effort it takes to add support for a new database type?
>>>>
>>>> It requires some effort. You need to add new Java classes and the
>>>> necessary tests.
>>>>
>>>> Have you checked out the SDB sources yet?
>>>>
>>>> If not:
>>>>
>>>> svn co
>>>> https://svn.apache.org/repos/asf/incubator/jena/Jena2/SDB/trunk/ SDB
>>>> cd SDB
>>>> mvn test
>>>>
>>>> You can use Eclipse and search for "Derby" which is one of the DBMS
>>>> supported
>>>> by SDB. This way you'll find the list of Java classes in SDB to
>>>> support Derby.
>>>> Then, you can read and study those classes. While you do that, you'll
>>>> learn the
>>>> design of SDB and you will get an idea on what it is required to add
>>>> MonetDB.
>>>>
>>>>> 2. Are there predefined extension points that allow adding a new
>>>>> database
>>>>> type easily?
>>>>
>>>> Yes, there are. Look at the super classes and interfaces from the
>>>> list of
>>>> classes above (i.e. searching for "Derby").
>>>>
>>>> There isn't an "how to add a new database to SDB" guide, however make
>>>> sure
>>>> you read the general SDB documentation (it does not hurt).
>>>>
>>>> Also, if you want to contribute an "how to add a new database to SDB"
>>>> you
>>>> are more than welcome to do so.
>>>>
>>>>> If so could you give me the name of some classes and config files,
>>>>> which
>>>>> are important to accomplish that task?
>>>>
>>>> You can start from:
>>>>
>>>> GenerateSQLDerby -- extends --> GenrateSQL
>>>> FormatterSimpleDerby -- extends --> FormatterSimple
>>>> StoreSimpleDerby -- extends --> StoreBase1
>>>> FmtLayout2HashDerby -- extends --> FmtLayout2
>>>> StoreTriplesNodesHashDerby -- extends --> StoreBaseHash
>>>> TupleLoaderHashDerby -- extends --> TupleLoaderHashBase
>>>> FmtLayout2IndexDerby -- extends --> FmtLayout2HashDerby
>>>> StoreTriplesNodesIndexDerby -- extends --> StoreBaseIndex
>>>> TupleLoaderIndexDerby -- extends --> TupleLoaderIndexBase
>>>>
>>>> Also look at:
>>>>
>>>> - JDBC.java
>>>> - DatabaseType.java
>>>> - StoreFactory.java
>>>> - SDB.java
>>>>
>>>> And the existing tests.
>>>>
>>>> May I ask you what motivates you in adding MonetDB?
>>>>
>>>> I've never used it myself and, indeed, I use TDB instead of SDB.
>>>> Transactions are coming, hopefully in the 0.9.0 release of TDB.
>>>>
>>>> Last but not least, it's not only about the code. You should be willing
>>>> to support the users of your code too. Once you add support for
>>>> MonetDB,
>>>> people will start using it and, as they use your code, they'll find
>>>> bugs
>>>> and they'll ask you for more features, eventually. You should be
>>>> willing
>>>> to put some effort in fixing the bugs, at least... and you can always
>>>> say
>>>> "no" politely to new features. Until, someone else, who really needs
>>>> the
>>>> new feature and he/she is willing to put some effort, will take over
>>>> and
>>>> push the software a step further.
>>>>
>>>> Once you start, you might have more specific questions on SDB design.
>>>> You can post your questions here or on [email protected]
>>>> mailing list. The more you demonstrate you put some effort the more
>>>> likely you'll receive helpful answers back from the SDB developers.
>>>> If you don't put enough effort and expect others will do it for you,
>>>> I am afraid, you risk to have not much back.
>>>>
>>>> To conclude, it you are motivated and you think you'll have fun doing
>>>> it (and you need it for your work): go ahead, it's not a terribly huge
>>>> task and it could be a nice contribution (in particular for all the
>>>> MonetDB users out there).
>>>>
>>>> Paolo
>>>>
>>>>>
>>>>> Thanks in advance!
>>>>>
>>>>> Best Regards
>>>>> Tobias Willig
>>>>>
>>
