[dotNetRDF-Support] Memory Leak with SparqlRemoteEndpoint against Sesame repository ?

[Thomas F. <tho...@sp...>]

Dear all

We have experienced a "system.outofmemoryerror" with the latest version of
dotnetrdf and the following code executed repeatedly (multiple times in a
loop) against a Sesame server :

Dim endpoint = New SparqlRemoteEndpoint(New Uri("
http://localhost:8080/sesame/repositories/my_repo"))
Dim queryString As SparqlParameterizedString = New
SparqlParameterizedString()
queryString.Namespaces.AddNamespace("annot", New
Uri(oAppSettingsReader.GetValue("BaseUriSite", GetType(System.String)) &
"/annotations.owl#"))
queryString.CommandText = "SELECT DISTINCT ?text WHERE {?annotation
annot:onContent <" & _uriDocument & "> ; annot:onContentPart """ &
ContentPart & """ ; annot:text ?text ; annot:isValid ""false""^^xsd:boolean
. }"
Dim results As SparqlResultSet =
endpoint.QueryWithResultSet(queryString.ToString)
For Each result As SparqlResult In results
    Console.WriteLine(DirectCast(result.Value("text"), LiteralNode).Value)
Next
results.Dispose()

(note the use of "results.Dispose" that does not seem to have any effect on
memory)

That version of the code, however, works fine (no memory leak) :

Dim store = New Storage.SesameHttpProtocolVersion6Connector("
http://localhost:8080/sesame/", "my_repo")
Dim queryString As SparqlParameterizedString = New
SparqlParameterizedString()
queryString.Namespaces.AddNamespace("annot", New
Uri(oAppSettingsReader.GetValue("BaseUriSite", GetType(System.String)) &
"/annotations.owl#"))
queryString.CommandText = "SELECT DISTINCT ?text WHERE {?annotation
annot:onContent <" & _uriDocument & "> ; annot:onContentPart """ &
ContentPart & """ ; annot:text ?text ; annot:isValid ""false""^^xsd:boolean
. }"
Dim results As [Object] = store.Query(queryString.ToString)
For Each result As SparqlResult In DirectCast(results, SparqlResultSet)
    Console.WriteLine(DirectCast(result.Value("text"), LiteralNode).Value)
Next

Do you see anything wrong or missing in the first snippet above that could
lead to a memory leak ? We are fairly new with DotNetRdf so we might have
missed something - in that case would someone be kind enough to fix the
first code snippet and send it back ? Or is it that Sesame server should
not be queried with a SparqlRemoteEndpoint ?

Thanks
Thomas & Eric

-- 
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*
*Thomas Francart* - Sparna
Consultant Indépendant
Data, Sémantique, Contenus, Connaissances
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