Report a Problem

If you find any problems with the site, please add a description of the problem to the bottom of this page, and we will look into it. Alternatively, you can also comment on the discussion page where you have found the problem.

Known Issues

General

• Some of the problems may already be documented on the SparqlExtension known issues page.

Querying external datasets

• We've noticed that the sparql endpoint for the CIA World Factbook is sometimes down, meaning that queries that reference it may not work occasionally. If you click here and nothing happens, then you know what's going on.
• Complicated queries using DBpedia may not work. We've received "HttpException: 509 Bandwidth Limit Exceeded" errors for some of the visualizations that previously worked.
  • See here for more issue on the problem from the DBpeida mailing list. It seems that the query should be made more concise to keep the data output below 10MB. I'm not sure if the "limit" parameter of sparql queries is pushed to the far end when using Jena/ARQ, otherwise using something like "limit 10" would be an easy way to fix this.
  • This query actually works now without any changes on our end, so maybe this will not be a problem in the future. See User:Alfredas/Charts/GeoMap for a sanity check. ChrisDavis 08:57, 11 October 2010 (CEST)

Templates, Appearance

• Template:EconomicSector needs to be updated so that it can retrieve labels for the pollutants, and not the urls. fn:substring does not work on the Special:SparqlExtension. See Energy_Sector for an example of this template in action.
• Look into Portal:Environment#Power_generation_CO2_emissions_per_GDP__per_country - the problem is that the country GDP is not set. Is this assigned automatically via the CIA World Factbook? We've had issues with their server being intermittently down.

Sparklines + Semantic Forms

• Some of the javascript used for visualizing sparklines conflicts with the "Add Another" feature of Semantic forms. ChrisDavis 18:01, 9 June 2011 (CEST)

CSV Export

• There is code for this in a previous version of the SparqlExtension. We should re-enable this (but specifically set up as an output format, not necessarily combined with a particular type of visualization). ChrisDavis 18:18, 9 June 2011 (CEST)

Google Visualization + External Datasets + SparqlExtension

• The SparqlExtension does not currently support visualization of data retrieved from an external endpoint (when specified using the endpoint parameter, using the service command may work).

Problem Creating New Power Plant

Attempting to add this plant returns a wiki error and I do not see how to fix it: (see this revision for text used to create power plant ChrisDavis 21:12, 20 September 2011 (CEST))

I'm not sure what happened. I tried to recreate it using the Form:Powerplant and it went ok (see Damariscotta mills for entry), and I wasn't able to find any related errors on the server logs. If you see the problem again, copy/paste the error message here and I'll look into it further. ChrisDavis 21:12, 20 September 2011 (CEST)

Energy Companies

• not all energy company pages exist // these pages can be created by creating them and populating them with the reference to the Template:EnergyCompany.
• I thus created http://enipedia.tudelft.nl/wiki/Afval_Energie_Bedrijf_%28aeb%29
• but the page then renders incorrect incomplete data. GerardDijkema
• I've changed the queries in the template to fix this. This was part of a known (but obscure) issue documented on the SparqlExtension page (search for "Here instead of using prefixes we are forced to use BASE keyword"). The problem is that queries can't be parsed if there is a prefix followed by the name of an object with parenthesis (or other non-alphanumeric) characters in it. The solution is to change references to a:SomePage(something) into <SomePage(something)>. ChrisDavis 21:37, 23 March 2011 (CET)
  • This ties into a larger need, which is that we should to set up something that can locate all of the queries spread throughout the wiki. Occasionally we become aware of simple patterns in the query syntax that may lead to incorrect results, but there's currently no easy way to track down all of these.
    • The get-it-done-in-an-hour solution would probably involve something that dumps out the page text from the MySQL database into a single text file for each page. With this, we can use command line tools like grep to efficiently find what we need.
    • Tasks like finding all the queries that don't return any results may be rather complicated, especially since we likely have 100,000+ queries on the site, and I'm not sure of an easy way to check all of them without evaluating them one by one.
  • The SMW community actually brought up this need at the last meeting, and whatever we develop should be communicated back to them. This wasn't just about Sparql queries, but it was also in reference to their ASK queries which are a bit more limited in their expressive power.

Queries that use the page name

• http://enipedia.tudelft.nl/wiki/Avr_Holding has the page on Afval Verwerking Rijnmond.
• this was generated from the data stored in Enipedia
• however, the correct name would be AVR Holding NV (instead of Avr Holding)
• how to change the page name & sync with the database? GerardDijkema
• The template is set up now to list all the facilities, and one way is to change name on each of these pages. I've also renamed the Avr Holding page to AVR Holding NV. ChrisDavis 23:02, 23 March 2011 (CET)

TODO

• Check if simply renaming the page is enough to fix references to that page contained on other pages (see above). If this is not enough, then this should be documented on the SparqlExtension page.
• Need way to find all the queries in use on the wiki in order to systematically fix some of the known issues.