Forum Discussion
Incremental refresh with polling expression
Go with the timestamp that has the most even distribution (likely the created date). Create a large enough "hot" window to cover most of the jitter (modifications happening soon after creation). For example make your "hot" partitions the last three months instead of the last month. Then use the Modified date to catch any entries that fall outside the "hot" window and manually refresh their partitions if needed. Plan on doing a full refresh (or a sequential manual refresh of all partitions) every now and then.
No, based on what you've said the problem is with the performance of the SQL queries themselves and nothing to do with Power BI. You need to get a DBA or someone familiar with SQL performance tuning to help you here.
These runtimes and row counts do not warrant incremental refresh. Your partitions should hold about half as many rows as you can fetch without hitting either a data source timeout or the 5hr limit for partition refresh.
Thank you cpwebb and lbendlin.
I asked the team to optimize the SQL queries, but they didn't come up with any solutions.
The problem was with refreshing our largest table, as I kept facing memory capacity errors.
I tried removing all the calculated columns from the table, which led to a successful refresh. (There were over 40 calculated columns.)
In an attempt to pinpoint the problematic columns, I removed 7 columns with seemingly complex queries, and again, the refresh was successful.
But, it appears that these specific columns might not be the root cause, as I kept them and removed the rest, and the refresh still succeeded. It seems like the table has a memory threshold that we shouldn't exceed!!
Is there a way to determine exactly which columns are causing the issue? Unfortunately, we can't remove them from the table.
Thanks again.
We ran into the same issue today. Ingesting a 46 GB dataflow works fine by itself, but as soon as you have calculated columns on that query there's a high likelihood of maxing out the machine memory (even on a 64 GB RAM PC). The spike clearly happens after the dataflow has fully loaded and the calculated columns are starting to be computed.
You can try to use DAX Studio Metrics to see what the estimated memory usage for these calculated columns is but it's not an exact science.
As much as it pains me to say it - as this is a calculated column it may be possible to push that change into the Power Query for the dataflow, or in your case into the SQL view.
+1 to this, not using calculated columns and implementing the same logic further upstream will be the best way to solve this problem.
I don't think there's any way of breaking down memory usage during refresh by calculated column, and even if there was it might not be helpful because variations in how objects are refreshed in parallel would affect the overall memory usage.
Which error message are you getting now exactly? Is it one of the errors mentioned here: https://learn.microsoft.com/en-us/power-bi/enterprise/troubleshoot-xmla-endpoint#resource-governing-command-memory-limit-in-premium ?
Thanks again lbendlin and cpwebb .
Does implementing the same logic of calculated columns in Power Query, which requires merging tables and some transformations, affect memory and performance again?
cpwebb Yes, the error message is: Resource Governing: This operation was canceled because there wasn't enough memory to finish running it. Either reduce the memory footprint of your dataset by doing things such as limiting the amount of imported data, or if using Power BI Premium, increase the memory of the Premium capacity where this dataset is hosted. More details: consumed memory 3464 MB, memory limit 3464 MB, database size before command execution 1655 MB.
We are on premium Embedded with A2 capacity (5 GB memory).
In our largest table (the table causing the issue), we have 56 columns, comprising 15 native columns, 20 calculated columns using only the 'RELATED' function, and 21 other calculated columns.
I randomly removed 7 columns, those that appeared more complex and that resolved the issue.
These are some of the columns I removed:
Media(Latest_Photo_jpg) =VAR Last_date =CALCULATE ( MAX ( Medias[CreatedOn]) )RETURNCALCULATE (LASTNONBLANK ( Medias[Media_URL_jpg], 1 ),FILTER (ALL(Medias),Medias[FollowUpId]=FollowUps[Id]),Medias[CreatedOn]=Last_date)Description(Latest_Notes) =VAR Last_date_1 =CALCULATE ( MAX ( Notes[CreatedOn]) )RETURNCALCULATE (LASTNONBLANK ( Notes[Description], 1 ),FILTER (ALL(Notes),Notes[FollowUpId]=FollowUps[ID]),Notes[CreatedOn]=Last_date_1)Follow-up URL = IF(FollowUps[IsFollowUp]= TRUE(),"https://--------.com/#/--------/------/"&FollowUps[Id],BLANK())Closed_Date = IF(FollowUps[Status] = "Closed",IF( FollowUps[LogHistory(Latest)] = BLANK(), FollowUps[CreatedOn] , FollowUps[LogHistory(Latest)] ), BLANK())Thanks a lot for looking into this. Much appreciated.