What I understand is that for each month your date field will show previous day's date if that is the case Tableau will treat entire data as incremental on daily basis (if my assumption is correct). Tableau needs some identifier which will help identify the new data. I would recommend using a key column instead of a date field. If you are using SQL db just add an identity column to your data and use that key as the identifier for incremental refresh.
Hope this helps.
Also check if the date field you are using is being imported in date format not text. This could be a possible reason.
My Dashboard is in Prod environment. and how can I add identity column to my data. Can you please help me out.
I am using ORACLE Datasource with prod credentials.
In my extract, im using unionall query taking fact tables.
Any other steps to reduce the refresh time apart from doing incremental refresh?
Incremental refresh is not working fine at my end. I have tried with many ways
My workbook has one extract. I have done Unionall taking 4 fact Tables & there are 5 dim tables joined to one Custom sql query.
Overall we have 18 Lakh records. I have tried with INDEX also.