I noticed some problem using Tableau with HiT ODBC/400 Driver (developed in my company).
I made many tests and saw that there are some strange Tableau behaviors.
In this post I will summarize our tests:
I opened the Metallkonten Schrott DB2 Hit.twb file.
By default it opens the "Blatt 1" sheet: it contains all data.
If I move the mouse over "Blatt 1 (2)" sheet without clicking, the preview doesn't show data of IMBGEW column:
If I move the mouse over "Blatt 3" sheet without clicking, the data of the KMMKKZ column are shown by the preview:
Then I click on "Blatt 1 (2)" and "Blatt 3" sheets, the data of the IMBGEW and KMMKKZ columns are not shown.
Why the data of "Blatt 3" are shown in the preview? Why they are not shown in the real table?
Now I am on "Blatt 3" sheet and press F5 (Refresh).
After the refresh both "Blatt 1 (2)" and "Blatt 3" tables are correctly filled with data:
Now I can move through the sheets and all the data are correctly shown.
We analyze the behavior of our HiT ODBC/400 Traces and we notice that:
- After the ODBC Login, Tableau ran on our driver the queries related to all sheets (for this reason the "Blatt 3" preview contains all data, Tableau receive them from our Driver).
- After the refresh on "Blatt 3" sheet, Tableau runs the queries related to "Blatt 1 (2)" and "Blatt 3" sheets.
Why it doesn't run the "Blatt 1" query?
It seems that recognize that some problem occurs with "Blatt 1 (2)" and "Blatt 3" sheets. Otherwise, he should run only "Blatt 3" query (the selected one) or all the queries ("Blatt 1", "Blatt 1 (2)" and "Blatt 3").
Tableau run "Blatt 1 (2)" and "Blatt 3" query two times, and our driver answer two times in the same way, with the same data.
We don't understand why Tableau doesn't show this data before the refresh.
Moreover, the "Blatt 3" preview contains all data before the refresh. This demonstrates that the data has been received by Tableau.
Since our HiT Driver sends always to tableau the same data, we don’t know why tableau doesn’t show this data.
We think this behavior could be related to a Tableau problem.
Does someone of you notice this problem?
Do you have any suggestion to fix it?