FCT aggregates and filters

sparql
fct

#6

Hi, could we have a http recording of the request?
In this way we can reproduce the bad xml.


#7

Are you saying that this doesn’t happen when using the LOD or DBpedia instances?

/cc @hwilliams @imitko


#8

@Sherman_Monroe: Note here are the details on creating a Virtuoso HTTP Recording … /cc @imitko @kidehen


#9

Hi Mitko,

Here is the request/response.

-sherman


#10

Hi Hugh,

Okay, I will generate a recording using this method also.

-sherman


#11

Hi Kingsley,

This is correct. It’s only in the FCT interaction from clients other than the /fct web interface.

-sherman


#12

Okay, what is the version of the FCT package installed? You more than likely need a later VAD, assuming you obtained yours from our download service.

The footer section of any FCT page reveals the version in use. Thus, if yours differs from a system that doesn’t exhibit these issues then you will need to upgrade.

/cc @hwilliams


#13

LOD does not exhibit this issue, and it’s version is v1.13.71. Our server does, and its version is v1.13.70. I’ll update to the latest VAD…


#14

I upgraded to FCT VAD version 1.17_git13, and the issue persists.


#15

URI Burner has the same issue.


#16

curl -X POST http://poc.vios.network/proxy/-start-http://data.vios.network-end-/fct/service --data ‘<query timeout=“16810”><class iri=“http://www.w3.org/2002/07/owl#Class”></class><text property=“http://www.w3.org/2000/01/rdf-schema#label”>Person</text><value datatype=“uri”>http://xmlns.com/foaf/0.1/Person</value><view limit=“15” type=“list-count” offset=“0”></view></query>’ -HContent-Type:text/xml -v

does anybody knows
why this reply with 400 error?


#17

The proxy URL has changed from:

http://poc.vios.network/proxy/-start-http://data.vios.network-end-/fct/service

to:

http://poc.vios.network/proxy/http/data.vios.network/fct/service


#18

Also, sometimes the Virtuoso instance at data.vios.network goes down and needs to be restarted. If you receive a bad response, please check if data.vios.network is up. I can restart it if it is down.


#19

do we know what is the reason Virtuoso server to go down?


#20

do we know what is the reason Virtuoso server to go down?

No, I don’t know why. Virtuoso spontaneously gives the message “The site is currently down for maintenance”. Sometimes restarting Virtuoso instance solves it, and sometimes the shutdown ends with error and the physical server has to be restarted.


#21

It may be an idea to kill with -11 the process to get core dump
or to attach with gdb and do ‘thread apply all where’


#22

Got it, thanks. I will try this to help with troubleshooting.


#23

@imitko

The LOD instance does not show symptoms of the filter bug. Is it possible to send the FCT VAD running at LOD? The filter bug is best exemplified in these two queries:

DBPedia (this instance is affected)
LOD (this instance is not affected)

Here are the two responses:

DBPedia Response (mal-formed)

HTTP/1.1 200 OK
Server: nginx/1.14.0 (Ubuntu)
Date: Sun, 10 Mar 2019 03:31:12 GMT
Content-Type: text/xml; charset=UTF-8
Connection: close
X-Powered-By: Express
access-control-allow-origin: *
access-control-allow-headers: Depth,DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Accept-Encoding
vary: Accept-Encoding
access-control-allow-credentials: true
access-control-allow-methods: GET, POST, OPTIONS
Content-Length: 7752

 filter (?s1 = <http://dbpedia.org/resource/Bay_of_Kotor>) .<fct:facets xmlns:fct="http://openlinksw.com/services/facets/1.0/">
<fct:sparql>     select ?s1p as ?c1 count (*) as ?c2  where  {?s1 a &lt;http://dbpedia.org/class/yago/BodyOfWater109225146&gt; . quad map virtrdf:DefaultQuadMap { graph ?g {  ?s1 ?s1textp ?o1 . ?o1 bif:contains  &#39;&quot;sea&quot;&#39;  . } }  ?s1 &lt;http://dbpedia.org/property/year&gt; ?s2 . ?s1 ?s1p ?s1o . } group by ?s1p order by desc 2 limit 30  offset 0 </fct:sparql>
<fct:time>955</fct:time>
<fct:complete>yes</fct:complete>
<fct:timeout>13560</fct:timeout>

LOD Response (well-formed)

HTTP/1.1 200 OK
Server: nginx/1.14.0 (Ubuntu)
Date: Sun, 10 Mar 2019 03:31:38 GMT
Content-Type: text/xml; charset=UTF-8
Content-Length: 8113
Connection: close
X-Powered-By: Express
access-control-allow-origin: *
access-control-allow-headers: DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Accept-Encoding
accept-ranges: bytes
access-control-allow-credentials: true
access-control-allow-methods: GET, POST, OPTIONS

<fct:facets xmlns:fct="http://openlinksw.com/services/facets/1.0/">
<fct:sparql>     select ?s1p as ?c1 count (*) as ?c2  where  {?s1 a &lt;http://dbpedia.org/class/yago/BodyOfWater109225146&gt; .  quad map virtrdf:DefaultQuadMap { graph ?g {  ?s1 ?s1textp ?o1 . ?o1 bif:contains  &#39;&quot;sea&quot;&#39;  . }}  quad map virtrdf:DefaultQuadMap { ?s1 &lt;http://dbpedia.org/property/year&gt; ?s2 . } filter (?s1 = &lt;http://dbpedia.org/resource/Bay_of_Kotor&gt;) . ?s1 ?s1p ?s1o . } group by ?s1p order by desc 2 limit 30  offset 0 </fct:sparql>
<fct:time>96</fct:time>
<fct:complete>yes</fct:complete>
<fct:timeout>13560</fct:timeout>

#24

The LOD instance exhibits the filter bug symptoms now also. This query returns mal-formed XML.

HTTP/1.1 200 OK
Server: nginx/1.14.0 (Ubuntu)
Date: Tue, 12 Mar 2019 21:26:46 GMT
Content-Type: text/xml; charset=UTF-8
Connection: close
X-Powered-By: Express
access-control-allow-origin: *
access-control-allow-headers: Depth,DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Accept-Encoding
vary: Accept-Encoding
access-control-allow-credentials: true
access-control-allow-methods: GET, POST, OPTIONS
Content-Length: 3412

 filter (?s5 = <http://dbpedia.org/resource/Orson_Welles>) .<fct:facets xmlns:fct="http://openlinksw.com/services/facets/1.0/">
<fct:sparql>     select ?s1 as ?c1 count (*) as ?c2 where { select distinct ?s1  {?s1 a &lt;http://dbpedia.org/class/yago/WikicatBlack-and-whiteFilms&gt; .?s1 a &lt;http://dbpedia.org/class/yago/WikicatDystopianFilms&gt; . ?s1 &lt;http://dbpedia.org/ontology/producer&gt; ?s2 . ?s1 &lt;http://dbpedia.org/ontology/distributor&gt; ?s3 . ?s1 &lt;http://dbpedia.org/ontology/director&gt; ?s4 . ?s1 &lt;http://dbpedia.org/ontology/starring&gt; ?s5 . } } group by ?s1 order by desc 2 limit 15  offset 0 </fct:sparql>
<fct:time>77</fct:time>

Note, this was not the case a couple of weeks ago.


#25

The below SPARQL query does not return the appropriate results. The subject ?s1 should have “STAR WARS” in its rdfs:label, but some of the results do not:

select distinct ?s1 as ?c1 ?o1 ?g where  { 

quad map virtrdf:DefaultQuadMap { 
  graph ?g {  
  ?s1 <http://www.w3.org/2000/01/rdf-schema#label> ?o1 . 
  ?o1 bif:contains  '(STAR AND WARS)'  . 
}}  

quad map virtrdf:DefaultQuadMap { 
  ?s1 <http://purl.org/dc/terms/subject> ?s2 . 
} 

optional { graph virtrdf:IRI_Rank_c {  
  ?s1 virtrdf:IRI_Rank_rnk_c_int ?srank1 . 
} }  

quad map virtrdf:DefaultQuadMap { ?s1 <http://purl.org/dc/terms/subject> ?s3 . } 

filter (?s3 = <http://dbpedia.org/resource/Category:Game_Boy_Advance_games>) . 

} 

order by desc (?srank1)