Post on 30-Dec-2015
description
SELECT R.bFROM R,S,TWHERE R.a = S.a and S.b = T.b;
SELECT R.bFROM R,S,TWHERE R.a = S.a and S.b = T.bORDER BY R.b ;
Joins vs. Plans (Interesting orders)
T T.bDC
RS S.bDC
DC R.aR
S.aDC S.bS
ST S.aDC
RST DC
In-memory directory
Number of Joins = 4Number of Plans = 1215
R.b
R.b
R.b
R SS T
R ST
RS T
2 join partitions
Order on R.a is interesting (useful) for Merge-join with S