Hi, I have a question about extracts and calculated fields.
I started designing a new dashboard, I wrote a custom sql to query some very large tables, run an extract (it took 40 minutes aprox) and then created many calculated fields and sets on visualization. When I want to refresh the extract, it doesn't finish because all the calculated fields (and sets) are calculated on the database instead of at run time and many huge queries are sent to de database. My question is: Is it posible to disable materialization of calculated fields and sets in data extracts so that they keep being calculated on runtime?
I am working with Tableau Desktop 10.0.
Thanks in advance.
Pablo.
Firstly, I don't know how to stop the materialisation at all.
Secondly, there's quite a few other options to fix this problem:
- the easiest might be - UPGRADE to 10.5. 10.5 was released a few days ago and the whole data engine has now changed to Hyper which is a lot better and faster and could help you without the need to change anything at all.
- stop using custom SQL. When I first started using Tableau I didn't believe this either BUT I've seen numerous examples over the years that have proven that custom SQL in Tableau forces it to do things slower sometimes. Instead, put your custom SQL in a view, or if that's too slow materialise it in a table (assuming that the data is not being updated constantly).
- check your record counts. Do you really need that many records ? You haven't mentioned how big the dataset is, but it sounds large. Things as simple as ... the base data is datetime down to the minute, but you only ever report on a day - then create a table (or view) in SQL that does a GROUP BY to the day level. The record count drops, the data is the same, Tableau runs faster.
Let me know how you go, let me know if you need more info
