@zericdamir We are having exactly the same issue, which is becoming very critical - since it is occurring on newly build DV workbooks, which are part of "analytical application" , having very "VIP consumers" in our company and they will be really not willing to wait until DV workbooks will be loaded (it takes 2 minutes for some of those DV workbooks).

What is our observation of this very very limiting behavior (I am going to create SR on this topic, but it would be good is someone from Product Development/Mgmt could have a look at this issue here: @Gabby Rubin-Oracle, @Mike Durran-Oracle, @Bret Grinslade - Oracle Analytics-Oracle ):

1. Those DV workbooks, where we are "hitting" this long loading time are having first canvas (which displays first) without any vizualization connected with data - it serves as a kind of "landing page", containing just links (with some textual descriptions) to other canvases of same workbook , thus containing just text box visualizations.
2. During loading of DV workbook, no logical SQL to BI Server are issued (from reason, mentioned in first bullet), so long time of loading is really not caused by firing/executing logical SQL (and physical SQL) to get data for visualizations
3. I tracked in browser session (via Developer Tools in browser), what is happening behind scene, there are plenty of requests/URL going to OAS box, but there is one call (internal API call) fired during DV workbook loading, whose execution basically consumes most time of DV workbook loading time
4. This API call is following: https://<hostname:port>/dv/ui/api/v1/modelmetadata/reportdatasetsmetadatajson and his response (JSON format) returns following data/metadata:
   List of data sets used in particular DV workbook along with all tables, join definitions between tables for data sets and also list of all columns of all data sets
5. This response can be pretty big (depending on no of data sets, no of tables, comprising those data sets and no of columns within those data sets) - for example for DV workbook, where loading takes for 2 minutes, size of this JSON response is 1,18 MB.
   So I will definitely (within this SR I am going to create) ask for justification of such API call , when DV workbook is open for consumer (we are not talking about switching to edit mode) - are all those information (returned from this API call) really necessary in "client" logic (browser) to perform just display of DV workbook for consumers (not editing it) ?
   How can performance of this API call (dv/ui/api/v1/modelmetadata/reportdatasetsmetadatajson) be improved via some settings (we need to definitely improve loading time, otherwise this will not be acceptable for our VIP end users for this "analytical application" in DV . And I don't really want to hear "advice from an ivory tower" like : Reduce number of data sets used in DV workbook (or reduce number of tables/columns in data sets) or split DV workbook into several ones, since every DV workbook has its own logic with all data in on place.

@Gabby Rubin-Oracle Hi Gabby, I have just created following SR "3-38865211321 : DV Workbooks initial loading takes long time - optimization needed" on MOS, where I have provided all information along with DVA and HAR file. So the best option would be to get in touch with support organization and ask for those artefacts . @Naveen Babu-Oracle can help you to get them. Thanks very much. Michal

Thanks to @ZericDamir and @Michal Zima for sharing this idea and submitting the SR. After an enormous campaign to involve our colleagues in the development of visualizations in Oracle DV, we are getting very negative feedback from key business departments and unfortunately we are facing very negative criticism that we have to continuously dampen. I believe this is some glitch that has escaped testing and the remedy from Oracle will be immediate (thanks @Gabby Rubin-Oracle for getting involved). Oh yeah, that's still something...