Stardog query through Studio

Support
1

Hi Team,
I am executing a query through Stardog studio and getting an error saying :
“Error executing query:invalid json response body at http:localhost:5820/DBName/query?reasoning=false reason: “toString()” failed” .
I am unable to retrieve what is failing and where it is failing as I am not able to see anything in the logs too.
Please help.
Also: the logs that i understand i have to look into is the “stardog” file located in STARDOG_HOME. Is there anything else i can look for?

Thank you!

2

Hi Smrati,

There should be a message in your stardog.log file. This is colocated with your database files.

Jess

3

Hi Jess,

Thank you for the quick response. The last lines that I see in log file is:

INFO  2018-04-18 09:33:57,661 [main] com.complexible.stardog.virtual.DefaultVirtualGraphRegistry:syncCache(176): Initializing R2RML registry
INFO  2018-04-18 09:34:05,875 [main] com.complexible.stardog.virtual.DefaultVirtualGraphRegistry:syncCache(185): Loaded R2RML registry with 9 sources
INFO  2018-04-18 09:34:07,359 [main] com.complexible.stardog.StardogKernel:start(2246): Initializing Stardog
INFO  2018-04-18 09:34:09,233 [main] com.complexible.stardog.cli.impl.ServerStart:call(233): Memory options
INFO  2018-04-18 09:34:09,233 [main] com.complexible.stardog.cli.impl.ServerStart:call(234): Memory mode: DEFAULT
INFO  2018-04-18 09:34:09,234 [main] com.complexible.stardog.cli.impl.ServerStart:call(235): Min Heap Size: 2.0G
INFO  2018-04-18 09:34:09,234 [main] com.complexible.stardog.cli.impl.ServerStart:call(236): Max Heap Size: 1.9G
INFO  2018-04-18 09:34:09,234 [main] com.complexible.stardog.cli.impl.ServerStart:call(237): Max Direct Mem: 1.0G
INFO  2018-04-18 09:34:09,235 [main] com.complexible.stardog.cli.impl.ServerStart:call(238): Max Mapped Mem: 115M
INFO  2018-04-18 09:34:09,235 [main] com.complexible.stardog.cli.impl.ServerStart:call(239): System Memory: 16G

Which is about starting the server. I dont see any error logs related to query execution. Does the stardog studio has same log file as Satrdog server?

4

Hi Smrati,

Sorry to hear that you’re having issues here. Two quick questions that might help to resolve this:

  1. What is the query that you’re trying to execute in this case, if you don’t mind sharing?
  2. I noticed that the URL in the error message is http:localhost:5820/DBName/query?reasoning=false, rather than http://localhost:5820/DBName/query?reasoning=false (missing the //). Was that just a typo in your post here, or are you actually missing the // after http: in your endpoint URL?

Thanks,
Jason

5

Hi Jason,

Sure:
I am executing the basic query:

select * where{
    GRAPH <virtual://DataManager>{
        ?s ?p ?o       
    }
}
  1. Sorry about that: it is a typo. Here is the error:
    image
    image.png743×106 11.4 KB

Thank you!

6

Thanks for the details. How many triples do you expect will be returned from the virtual graph query? We have an open ticket for an issue in Stardog Studio when results are too large for the client to parse. It’s likely this limitation that you’re hitting. Can you try adding a LIMIT to the query?

Jess

7

Hey Jess,

Thank you so much!!
I was able to execute the query after applying LIMIT to it!!

Thanks and Regards!

1 Like
8

Glad it’s working!

Jess

9

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