Couldn't load the model schema (Sept & Oct releases)

[rlooney]

We're building a custom connector to an ODBC driver.

There is a specific table that is no longer working in the Sept & Oct releases of Power BI Desktop.  In the August release of Power BI Desktop, it works just fine.  Our connector and ODBC driver don't change (or error) when testing which seems to indicate the error is within Power BI Desktop.

The error is "Couldn't load the model schema".  The underlying message is "[Expression.Error] The name '3b8566cf-af93-4ca1-b887-2dbc8b7ecee8' wasn't recognized.  Make sure it's spelled correctly."  That GUID is not a GUID in our system so we're assuming it is internal to Power BI.

When this error happens, the table schema does load on the relationship view.  However, the table and columns are not shown on the Report view under the Fields pane.

Please let us know if we can provide additional information to help get this issue fixed or if this is a known issue.

[rlooney]

We were able to isolate this further.   The issue isn't isolared to the Sept & Oct releases - it will break in Aug as well.

It is realted to having a table named "Measures" in the data source.  If that table is the first table in the list of tables and you're using DirectQuery, it will error.   

If you do these steps, it works fine:

 * Create 2 tables named "Measures" and "Test" in the data source

 * Connect to them using DirectQuery mode connector via ODBC

 * Select the "Measures"  table and click "Load".

(you should see the error)

Note that it's renaming "Measures" to "Measures 1" in the relationship window.

If you follow the above steps in Import mode, it works fine.

If you follow the above steps and select "Test" and then "Measures", it works fine.

We were able to duplicate this using SQL Server as the underlying data source and the example SQLODBC Data Connector as well.  Using the native SQL Server "Get Data" path works fine if you select "Measures" first, and you'll see it reflected as "Measures 1".

[brianhartman]

We identified this problem with Power BI Desktop recently thanks to people submitting error reports from within the product.  This should be fixed in the November release.

[v-qiuyu-msft]

Hi @rlooney,

I have reported this issue internally: CRI 90294157 to track this issue. Will update to you if I get any ifnormation. 

Best Regards,
Qiuyun Yu 

[v-qiuyu-msft]

Hi @rlooney,

I got information below internally: 

I'm looking into the issue and will fix the sample code if issue is confirmed.  In the meantime, just want to let customer know that there is SQL Connector he can use instead of using sample SQL ODBC connector.

Best Regards,
Qiuyun Yu

[rlooney]

@v-qiuyu-msft -

Did you see the above note from @brianhartman?  He said the issue has been found and fixed inside Power BI for the November release.

We will confirm next week when the release comes out, but this appears to be resolved now.

[v-qiuyu-msft]

Hi @rlooney,

I have consulted it internally to double confirm the fix. Will keep you update once I get information. 

Best Regards,
Qiuyun Yu 

[v-qiuyu-msft]

Hi @rlooney,

I confirmed that there is no ETA currently. 

There are couple of workarounds to get around this issue

1. SQL ODBC connectors are not officially supported with PBI Desktop today. The customer can use the traditional and supported way of connecting to SQL Server by selecting “SQL Server Database” from the list of sources
2. Avoid “Measures” or “Measure” as a table name which has special meaning in PBI Desktop
3. Choose “Measures” second to some other table which the user has already done

Best Regards,
Qiuyun Yu 

[rlooney]

Hi @brianhartman

I've confirmed this is still broken in 2.64.5285.701 64-bit (November 2018).

Any insight on when this might be released?  @v-qiuyu-msft says no ETA?

Thanks for you efforts here!

[v-qiuyu-msft]

Hi @rlooney,

I confirmed it again, the fix will be in the February release.

Best Regards,
Qiuyun Yu