I have two source tables . Each table coming from different database system. ( One is from Oracle and another one is Sybase IQ). But join is not going to push down due to different source databases. But one table have large volume ( 10 + million) of data and second one I have less than 100 records. Due to not push down I need to read all 10+ million data to join.
Is there any way to push down the join between two different database tables.
Have you tried using the join rank feature? Set the smaller table to a larger number than the larger table.
Another way to do this is to get data from the smaller table through a lookup function. If you are applying a filtering expression against the smaller table that would limit the result set from the larger table then this won’t work.
Still another way to make this work is to copy the smaller table into the database that has the larger table. Then do the join in the database where both tables reside.
If you don’t want to make a physical copy of the data you may be able to set up a view in the database where the larger table resides. The view would connect to the small table. Since you’re using different DBMS in this case it might not work to make a cross-DBMS view.
(BOB member since 2009-04-30)
(BOB member since 2007-09-12)