Welcome
back to this week’s edition of the Power BI blog series. This week, we discuss composite models.
In December 2020, Power BI launched the
Preview of DirectQuery for Power BI Datasets and Analysis Services. Since then, Microsoft has been working on
improving this feature to get it ready for General Availability. There were various improvements made, such as:
- support for SQL
Server Analysis Services Tabular models (version 2022 required) - ensured display
folders, sort by column properties and format strings persist - introduced sub
setting and the ability to connect to perspectives - users may now view
a report built using this feature with Read permissions / Viewer role instead
of Build permission / Contributor role.
Models built using this feature are
referred to as composite models. Originally known as “DirectQuery for Power BI
Datasets and Analysis Services”, this name is now superseded as it has served
its purpose during the Preview period to be able to clearly identify that this
was a Preview feature.
This update acknowledges the end of the
Preview period: composite models based upon Power BI datasets and Analysis
Services Tabular models are now Generally Available and fully supported on
Premium, PPU and new Pro workspaces.
Microsoft will announce General Availability
for existing Pro workspaces later as the Power BI team finish the
backend changes required. It should be
noted that as these back-end changes are happening, users might no longer need
Build permissions to view a report built using this feature, but instead they
can rely on just Read permissions. When
this happens, you can safely take away the Build permissions for your
consumers.
If you are currently using Pro
workspaces and want to switch over to the Read permission model right away, you
can. However, it requires you to create
new workspaces and host the datasets and reports there. As a reminder, going forward you will need to
enable the ‘Allow XMLA endpoints and Analyze in Excel with on-premises
datasets’ setting enabled in your tenant to use this feature.
Furthermore, when the Preview began,
any consumer of a report that leveraged a composite model based upon a Power BI
dataset was required to have Build permissions or the Contributor role. Since then, Power BI has changed this for
Premium and PPU workspaces: readers of reports based upon datasets in Premium
or PPU workspaces just require Read permissions (or the Viewer role).
However, for most Pro workspaces Build
permissions are still required in the scenario above. As mentioned above, Microsoft is still making
backend changes to align the Pro workspaces with the Premium and PPU workspaces
so everyone consuming these reports will just require Read permission or the
Viewer role, regardless of the workspace type the data is stored in. Apparently, these changes are still underway
and are taking longer than expected!
This does have an impact for us end
users:
- if you only use
Premium / PPU workspaces, Read permission is required to view a report - if you use a
mixture of Premium / PPU and Pro workspaces or use Pro workspace exclusively,
some of your reports might currently only require Read permissions while others
will still require Build. The ratio of
these will shift over time to the vast majority just requiring Read as Microsoft
completes the backend changes - if you currently
use Pro workspaces, some datasets will not benefit from the backend changes and
will still require Build permissions, even after the back-end changes are
completed. This includes datasets that:
- use one or more unsupported sources and / or
- consume a large amount of memory, which is true for about 0.03% of all
datasets.
Microsoft has stated it has seen numerous
users making DirectQuery connections to unsupported sources, such as usage
metrics and real-time data sets. Whilst
during the Preview you might not have received an error when using these
sources, you will start seeing an error going forward as “loose ends are
tightened”. Even if you do not see an
error, you should still use this feature with supported sources. The unsupported sources are documented, so
please make sure you use supported sources for your reports that rely on this
feature now or trouble may be finding you out in the very near future…
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