How to adjust performance of table joins in PROC SQL

Nico Chart_21517

You can try using the 'magic' option (a.k.a. '_forced_join_type') to provide hints to PROC SQL to encourage it to choose alternative JOIN algorithms.

magic=101 means the same as _forced_join_type=nested

magic=102 means the same as _forced_join_type=merge

magic=103 means the same as _forced_join_type=hash.

Other unpublished debug methods for PROC SQL:

PROC SQL feedback _method _print_join_choice _print_join_sizes;

The log will then give us a better idea of which join algorithm PROC SQL chose to use and why.