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Mulder2542's avatar
Mulder2542
Frequent Visitor
3 years ago

Query folding creates unusable queries in merge

We use Snowflake as a data source, which (unofficially?) supports query folding. This normally works, but when joining large tables via "Merge Queries" we keep running into the issue that the resulti...
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  • lbendlin's avatar
    lbendlin
    Icon for Super User rankSuper User
    2 years ago

    Don't merge on columns that have nulls. Don't merge at all.  Let the data model do the dirty work.

  • Mulder2542's avatar
    Mulder2542
    Frequent Visitor
    1 year ago

    Yesterday I worked with an old dataset/sematic model, without a workaround in place for this issue (it did  nevertheless work because there was less data involved) and noticed that the (preview) data appeared rather quickly. After further examination, it appears that even though PowerBI still produces the same inefficient query, Snowflake seems to handle it fine now. Could be a workaround on their side?

    • _onto_'s avatar
      _onto_
      Icon for Helper I rankHelper I
      10 months ago

      Could it be that you have a PRIMARY KEY hint in the Snowflake table?