Forum Discussion

robarivas's avatar
robarivas
Post Patron
9 years ago

Large Table performance

I'm connecting to an IBM DB2 database (z/OS) via ODBC (cause I could never get the built-in connector to work). Most tables are viable. However, I cannot find a way to get the transactions table data...
Need Help
yan's avatar
yan
Advocate I
9 years ago

Same issue here on a simple group by - no query folding so PD/PQ loads it all (20M rcds) before aggregating...

I use Teradata through ODBC because it is the only option (still) to authenticate through LDAP.

 

I bet it is due to the use of ODBC: PB/PQ doesn't know what DBMS it needs to translate the SQL too.

 

(De)selecting columns though does translate to native SQL, probably because it is pretty standard. Anything invoking a WHERE or GROUP BY is not.

 

The alternative is to copy/write your own "hardcoded" custom SQL in the data source step. Not ideal if you want business users to share a baseline and create their own steps (unless folding after that is not a must).

robarivas's avatar
robarivas
Post Patron
9 years ago

Finally got a "proper" connection to the DB2 database...no more ODBC. I'm using the Microsoft driver. However, still no Query Folding!!! :smileyfrustrated:

 

I wonder why. Anyone have a theory? Again, all I'm doing is a simple dates between filter on a date column (as my test of Query Folding).

  • robarivas's avatar
    robarivas
    Post Patron
    9 years ago

    Would still love a response (Microsoft maybe??). The inability to leverage my transactions table seriously hampers my ability to fully adopt Power BI. One step or no step (i.e., Scheduled) Refresh is an impossibility because of this.

     

    And why would query folding happen for certain columns but not for others, such as (crucially) my Posting Date column???