Introducing horizontal fusion in DAX

Horizontal fusion is a new optimization technique available in DAX to reduce the number of storage engine queries. In this video, we introduce this optimization with some examples.
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[@augustotanaka]

Beautiful explanation, good to know MS is pushing all these optmizations. Thanks for the video Alberto!

[@paulgallagher2987]

Awesome Stuff as always! Thanks Alberto.
I noticed this in the preview options last night and immediately looked for a video on it. As if by magic, you launch one the next day!

[@louism.4980]

Thank you so much, always enjoy watching your videos! :)

[@allmazd]

Thank you for the excellent explanation!

[@sherifffruitfly]

Looks like "predicate pushdown" to me - very cool!

[@Bharath_PBI]

Nicely explained! Thank you 👍

[@NateHerring1]

Who is this Bizarro Alberto 😆? Great content as always!

[@HeliSal700]

Thank you for the explanation. This feature looks very helpful.
I have two questions:
- Did you notice any negative impact after enabling this feature?
- How can I know which aggregation is supported by the Storage Engine and thus supported by horizontal fusion?

[@SQLBI]

It depends - you can find more details in the article.

[@jorgeeduardomoltenimoreno3048]

Thank you!

[@MPA76]

Thank you Alberto! Really matters to know internals

[@ZappPSR]

Questions:
1) Do we have to activate it in Power BI Desktop and on Power BI Online Service too?
2) It is a global preview feature, not by file. So, If I enable this global experimental feature in Power BI Desktop and publish a report, all other reports will have horizontal fusion enabled?
3) The more important one: Is it safe at this stage to enable it?
Maestro, thanks again for keeping us to speed.

[@SQLBI]

It's a feature in preview on PBI Desktop only, once it's GA it should be enabled on Power BI Service, too. It is not a flag by-report.

[@ladegaanthony1376]

Thanks for the great explanation.
Why is this amazing feature not enabled by default ?

[@SQLBI]

It will be enabled by default as soon as Microsoft completes to test it.

[@timgray7859]

Great video, as always! Does this horizontal fusion only work in a single measure, or does it also take into account multiple measures on the same visual to optimize the scans? Example being a visual showing sales amount and a separate measure showing margin.

[@SQLBI]

Potentially it could work on differente measures using "compatible" aggregations.

[@workstuff5253]

Don't forget the other, original, type of "fusion" bought to me by DAX. Confusion!

[@joshholt2877]

Is there a situation where this optimization would actually be a hindrance?

[@SQLBI]

Potentially, there could be cases where it's counterproductive, even though it should be extremely rare.

[@lucasshipsides1510]

sweet beard 👌👌👌👌👌👌👌👌👌👌👌👌

[@noahhadro8213]

since this is in "Preview" will I see this enabled in the service or do we have to wait?

[@SQLBI]

Not sure, probably it will be rolled out later.

[@DataHacker]

So basically, no drawbacks when it is enabled . I winder why it is not enabled by default. There must be some catch there

[@SQLBI]

It will be enabled by default - it's initially in preview to verify there are not regressions.

[@kldpmishra]

Alberto Sir In this video it is hard to listen you.

[@SQLBI]

Please, can you clarify? Is there an audio recording issue?

[@PerfectPotion]

@@SQLBI You need to crank the volume up pretty high to hear anything.

[@timgray7859]

@@SQLBI Sounds good to me, must be a local issue

[@johnhenryb27]

@@SQLBI Out of sync slightly to me - aud and vid.

[@egbertdejong6377]

No issue here