Andy Seaborne wrote:
Hi,
Could we have things like slow queries on the user list to start with,
please? If there's an underlying issues, then move to JIRA but until
there is an addressable issue, JIRA does not work for me for discussing
query design. It's quite possible in SPARQL to write very expensive
queries,
SELECT * { ?s ?p ?o . ?x ?y ?z }
Andy, please, don't suggest too wild ideas to people. ;-)
and ARQ/TDB's design means such queries will execute and finish
eventually. But its N^2 results on a database of N. And N tends to be
a decently large number. In fact, it wouldn't even use very much memory
for that query, because of internal streaming.
Andy
On 03/02/11 15:52, Benson Margulies (JIRA) wrote:
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https://issues.apache.org/jira/browse/JENA-40?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12990142#comment-12990142
]
Benson Margulies commented on JENA-40:
--------------------------------------
Changing the OPTIONAL's to UNION and adding the necessary constraint
to both of them also makes it run in reasonable time/
Query that runs more or less forever
------------------------------------
Key: JENA-40
URL: https://issues.apache.org/jira/browse/JENA-40
Project: Jena
Issue Type: Bug
Components: TDB
Reporter: Benson Margulies
Attachments: r.rq, yk.txt
Using the data set you have from me, the following query, which looks
very much like a series of other queries that run quite rapidly,
shows no sign of finishing.
