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xander2121's avatar
xander2121
Frequent Visitor
4 years ago
Solved

Step folding Unknown indicator error behind?

Hello everyone,   In the Step foldin indicators there is an "Unknown" indicator which represents absence of query plan due to an error. How do I find out that error? 
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  • jjgb's avatar
    jjgb
    4 years ago

    Hi xander2121, 

     

    The step indicators are calculated by using the query plan. In "M", the query plan can be obtained by calling Value.Expression(Value.Optimize(...)) on the affected step.

     

    For example, a known bug (under investigation) that will produce an "Unknown" step indicator is this:

     

    let
      Source = Sql.Database("some_server", "some_database", [CreateNavigationProperties = false]),
      Navigation = Source{[Schema = "dbo", Item = "Tags"]}[Data],
      #"Removed top rows" = Table.Skip(Navigation, 4)
    in
      #"Removed top rows"

     

    I can obtain the error message by adding a new step that obtains the query plan for the affected step:

    let
      Source = Sql.Database("some_server", "some_database", [CreateNavigationProperties = false]),
      Navigation = Source{[Schema = "dbo", Item = "Tags"]}[Data],
      #"Removed top rows" = Table.Skip(Navigation, 4),
      QueryPlan = Value.Expression(Value.Optimize(#"Removed top rows"))
    in
      QueryPlan
     
    Hope this helps. If you can, please share your query so we can track this as a bug.
     
    Regards,
    Jorge
jjgb's avatar
jjgb
Microsoft Employee
4 years ago

Hi xander2121, 

 

The step indicators are calculated by using the query plan. In "M", the query plan can be obtained by calling Value.Expression(Value.Optimize(...)) on the affected step.

 

For example, a known bug (under investigation) that will produce an "Unknown" step indicator is this:

 

let
  Source = Sql.Database("some_server", "some_database", [CreateNavigationProperties = false]),
  Navigation = Source{[Schema = "dbo", Item = "Tags"]}[Data],
  #"Removed top rows" = Table.Skip(Navigation, 4)
in
  #"Removed top rows"

 

I can obtain the error message by adding a new step that obtains the query plan for the affected step:

let
  Source = Sql.Database("some_server", "some_database", [CreateNavigationProperties = false]),
  Navigation = Source{[Schema = "dbo", Item = "Tags"]}[Data],
  #"Removed top rows" = Table.Skip(Navigation, 4),
  QueryPlan = Value.Expression(Value.Optimize(#"Removed top rows"))
in
  QueryPlan
 
Hope this helps. If you can, please share your query so we can track this as a bug.
 
Regards,
Jorge