Exists vs Left Keep

[#1]

HI,

I first load a smal table with 2000 rows.
Then I want to load rows from a big table, >100 miljon rows, but only rows with an Id that matches the Id in the first row...

How sould I do this to get best performance, exist or Keep?

tab1:
Load Id, col2,col3 from source1.tab;
tab2:
load Id,col4,col from source2.tab where exists(Id);

or

tab1:
Load Id, col2,col3 from source1.tab;
tab2:
left keep load Id,col4,col from source2.tab;

BR
Hans

[disqr_rm · Accepted solution]

I would go with EXISTS. Reason: Left keep will load everything first and then keep the relavent records. But EXISTS will only load records where condition is true. And EXISTS still good for QVD optimized loads. Hope this helps.

[#3]

Did I verify this, I think I did?
It might be ok but I just didn't verify it... Sorry.

One thing. These two funktions is virtually the same, and where the left keep is of a later date...
Why isn't that funktion better performing?