What does "push a join predicate down" mean ?

I read this stuff several times. And there is this hidden param. _PUSH_JOIN_UNION_VIEW that's specifically been set up to "enable pushing join predicate inside a union view" as X$KSPPI's doc. states it.

But I understand *nothing* to the sense of "pushing a join down"..., and found nothing in the forums to enlighten me.

Thanks.
Spendius Received on Mon Jul 12 2004 - 05:24:49 CDT