Exclamation marks mean, datasource is not valid anymore. It can occur, if the source table/fields are dropped or changed. Tableau workbook will still carry the original metadata and will try to query the database.
You could try the below steps
1) To open the workbook and delete the erring columns from the workbook altogether and save it.
2) Also, editing the datasource and making sure the columns are same as in DB, (and hitting update now) should remove the errors.
3) Regenerate extract if you have to.
4) Save the workbook and extract again.
I published the data source to the server and then have my workbook pull the data from the server. My workbook is trying to pull the hidden data fields which are not present in the published data source. This will cause it to fail to find the fields and show the exclamation points. As this is a new feature in 10.2, I believe it is a bug. My workbook should not be attempting to pull hidden data fields.
You published the datasource to reflect the changes in database, which is good. But did you edit the workbook to remove the old metadata and republish it?
I never published the workbook to begin with.
Downloaded my old salesforce published data source from 10.1. It contained hidden fields already.
Opened it in Tableau 10.2 in a new workbook.
Added the Oracle data join that is a new feature in 10.2.
Republished the data source and allowed Tableau to automatically swap me to the published version.
Pulled an extract with some filters.
Data source now shows all my hidden fields as errors.
Deleted all those errors. Did some work building a dashboard.
Next day I refreshed the extract and the errors are back.
Is the server on 10.2 as well? Reason I am asking is, You cant publish 10.2 content to a 10.1 server.
If that is not the case too, then, Is it possible to re-do the datasource from scratch on 10.2 and try publishing the datasource again?
Yes the server is on 10.2
I did a 'Export data to csv' and it created a csv containing ALL data from Salesforce. This includes everything I had hidden and the fields that were erroring. It appears my published data source is completely ignoring hidden fields. My workbook is also completely ignoring hidden fields and attempting to pull the data in. It seems to be succeeding in pulling the data in but getting confused when it displays it in the workbook.
I'll try rebuilding it from scratch...
Rebuilding the connector from scratch has the same effect. The initial data pull is fine. When refreshing the extract, it completes the data pull. It tosses an error when I try to do anything and requires me to re-pull the extract. The next data extract pulls all data and ignores hidden fields.
Ok. Best bet, I think, is to reach out to support. They usually call you back in 2 to 3 days. You can walk them through the issue over remote session. Lets see if they have encountered this.