Why are previews in Power BI so extremely slow even with tiny tables? (Mostly rhetorical question)

[kondado]

Hi there,

Before anyone replies with the usual stuff that you also find in all sorts of tutorial blogs or Microsoft official documents: I am not talking about huge tables. Then, why are Power BI Desktop previews inside the Power Query Editor window always so exasperatingly slow?

I can use DBeaver (an SQL tool) side by side with Power BI Desktop. I have a table that has literally TWO rows albeit it has a column with two data blobs which are barely 40KB, so I guess that should be a non-issue. Why does DBeaver take just a few seconds to load the table and Power BI loads and loads and loads and loads until it finally shows something?!

Please, Microsoft, do something to improve this. At least provide a window showing what is actually happening and why it is taking so long. Not just some dots flying over the screen. This may be ok for basic users, but not for devs!!

[Royel]

Hay @kondado its not a problem for power bi desktop. Lets ensure few things to overcome the issue. 

• Try to make sure your computer has at lest 16 GB ram ( 4 GB or more recommended) 
• Using (task Manager) Check how much memory you have remain and power bi takes what percentage.
• If its too slow do not run chrome, skype and power bi desktop together.
• Set power bi desktop configuration (File -> Options & Settings -> Options). See the attached image, it will give power bi desktop highest privillage to load data. 

• Import is more fastar than Direct Query. 
  
  I hope after maintaining this, you will get better performance. 

[kondado]

Hello @Royel ,

I know you're just trying to help, but this has nothing to do with system performance.

I'm running PBI Desktop on a Core i7-11700K that's even overclocked, SSD, and 32 GB of RAM. As stated in my OP, DBeaver loads a table with two rows in a matter of seconds, whereas PBI takes comparatively forever. Also, this has nothing to do with DirectQuery or Import, as we are talking about previews here.

There seems to be some sort of internal issue with how PBI handles previews.

[Eduardo_Suela]

In my team we have been experiencing those slow performance.

Same situation: everyone on i7, 16GB and "small data sets" allways less than half a million records. Some times about thousands. Query goes very very slow.

One situation we have experienced: same files built about 8 months ago, now look like a lot slower to refresh.

When we build load the previews, usually refresh all is soooo slow.

It looks less soooo slow if we refresh the queries in order. Maybe we are entertained and looks a tiny bit faster.

These slowness we have been experiencing has started in spring more or less

[Eduardo_Suela]

I also tryied clearing the caché. It doesn't work.

[Greg_Deckler]

@kondado Completely feel your frustration with this. If I had a nickle for every minute I've watched those 5 dots cycle across the screen I'd be retired by now. I do find that this is situational. Previews for local files tend to be much faster while things like loading previews for Dynamics 365 CRM take forever for example. I will also state that it seems to have gotten worse over time. What's more, I've even noticed that while it might take 10 minutes for a preview of 1,000 rows to show up, when I actually load the data, all the data (often 100,000 rows or more) is loaded in like under a minute. It's really bizarre.

[kondado]

Hello @Greg_Deckler, thank you for taking the time to post your experience with this. It means a lot, especially as a super user. I hope MS will update this sooner rather than later as it is annoying and time-consuming. Cheers.