WdBrowser - Unexpected error on items with many instances

[tholzheim]

When searching for Q13442814 the following error occurs

'WikiDataBrowser' object has no attribute 'propertySelection'

Traceback (most recent call last):
  File "wd/wdbrowser.py", line 670, in selectItem
    await self.trulyTabularAnalysis(self.tt)
  File "wd/wdbrowser.py", line 480, in trulyTabularAnalysis
    if self.propertySelection is None:
AttributeError: 'WikiDataBrowser' object has no attribute 'propertySelection'

[tholzheim]

The issue emerges from this section: https://github.com/WolfgangFahl/pyOnlineSpreadSheetEditing/blob/e265a6358cb29c1d2a038a2dfabd5086e0ad424f/wd/wdbrowser.py#L667-L672

The methods have all their own exception handling and also define properties for the following methods to use. Thus, side effects occur of the case that expected properties are not defined.

await self.getCountQuery(self.tt),  #defines: ttcount
await self.getMostFrequentlyUsedProperties(self.tt),  #uses: ttcount | defines: ttquery,propertyQueryDisplay
await self.getPropertiesTable(self.tt, self.ttquery), #uses: ttquery  | defines: propertyList, propertySelection, ttTable
await self.trulyTabularAnalysis(self.tt) #uses: propertySelection

Resolved these side effects by removing the global exception handling within the methods and instead use more specific Exception handling such as:

try:
    self.propertyList=tt.sparql.queryAsListOfDicts(ttquery.query)
except EndPointInternalError as ex:
    if self.isTimeoutException(ex):
        raise Exception("Query timeout of the property table query")

[tholzheim]

With these fixes for the search Q13442814 we now get:

• with wikidata: Query timeout of the property table query
• with qlever: QueryBadFormed [...] Tried to allocate 14029MB, but only 11362MB were available. Clear the cache or allow more memory for QLever during startup

Thus, the Exception for items with many instances is not resolved but now the error messages indicate that the issue depends on the endpoints

[tholzheim]

The dependency and and possible side effects still need further investigation e.g. https://github.com/WolfgangFahl/pyOnlineSpreadSheetEditing/blob/8a19ba34c24cbeef7dcd04bfd07c46a0406244a8/wd/wdbrowser.py#L633-L637

[WolfgangFahl]

this might be a motivation to work on our own endpoint especially since the Wikidata Workshop paper has been accepted.