Why NESTED LOOP Not Allowed for FULL and RIGHT Join.
Started by Rushabh Lathiaover 18 years ago2 messageshackers
Hi,
can anyone let me know that why Nested Loop path is not allowed if jointype
are JOIN_RIGHT or JOIN_FULL?
At match_unsorted_outer(), we having case where nestjoinOK = false if there
are
JOIN_RIGHT or JOIN_FULL.
match_unsorted_outer()
{
....
case JOIN_RIGHT:
case JOIN_FULL:
nestjoinOK = false;
..
}
wondering why ?
Regards,
Rushabh Lathia
rushabh.lathia@EnterpriseDB.com
Re: Why NESTED LOOP Not Allowed for FULL and RIGHT Join.
"Rushabh Lathia" <rushabh.lathia@gmail.com> writes:
can anyone let me know that why Nested Loop path is not allowed if jointype
are JOIN_RIGHT or JOIN_FULL?
How are you going to track which of the inner-relation rows never find a
join partner and hence need to be emitted on their own?
regards, tom lane