[
https://issues.apache.org/jira/browse/JENA-624?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15005470#comment-15005470
]
Andy Seaborne commented on JENA-624:
------------------------------------
There are some ordering problems in find results:
{noformat}
public static void main(String ... a) {
DatasetGraph dsg = DatasetGraphFactory.createTxnMem() ;
dsg.add(SSE.parseQuad("(_ :s :p :o)")) ;
dsg.add(SSE.parseQuad("(:g1 :s1 :p1 :o1)")) ;
Node p = SSE.parseNode(":p") ;
Node p1 = SSE.parseNode(":p1") ;
System.out.println("Default graph") ;
Iterator<Triple> iter = dsg.getDefaultGraph().find(null, p, null) ;
Iter.print(iter);
System.out.println() ;
System.out.println("find/4") ;
Iterator<Quad> iter2 = dsg.find(null, null, p, null) ;
Iter.print(iter2);
System.out.println() ;
System.out.println("find/4") ;
iter2 = dsg.find(null, null, p1, null) ;
Iter.print(iter2);
System.out.println() ;
}
{noformat}
gives the output (annotated):
{noformat}
Default graph
http://example/p @http://example/o http://example/s
{noformat}
Order is POS - should be SPO.
{noformat}
find/4
[urn:x-arq:DefaultGraphNode http://example/p http://example/o http://example/s]
{noformat}
Same - should be SPO.
{noformat}
find/4
[http://example/p1 http://example/g1 http://example/s1 http://example/o1]
{noformat}
Order is PGSO- should be GSPO
> Develop a new in-memory RDF Dataset implementation
> --------------------------------------------------
>
> Key: JENA-624
> URL: https://issues.apache.org/jira/browse/JENA-624
> Project: Apache Jena
> Issue Type: Improvement
> Reporter: Andy Seaborne
> Assignee: A. Soroka
> Labels: java, linked_data, rdf
>
> The current (Jan 2014) Jena in-memory dataset uses a general purpose
> container that works for any storage technology for graphs together with
> in-memory graphs.
> This project would develop a new implementation design specifically for RDF
> datasets (triples and quads) and efficient SPARQL execution, for example,
> using multi-core parallel operations and/or multi-version concurrent
> datastructures to maximise true parallel operation.
> This is a system project suitable for someone interested in datatbase
> implementation, datastructure design and implementation, operating systems or
> distributed systems.
> Note that TDB can operate in-memory using a simulated disk with
> copy-in/copy-out semantics for disk-level operations. It is for faithful
> testing TDB infrastructure and is not designed performance, general in-memory
> use or use at scale. While lesson may be learnt from that system, TDB
> in-memory is not the answer here.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
