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Input : search lattice with A() and S() edge costs
for (level k = 0 to N -1 do begin
Generate-Plan(
)
;
for (each Group-by g in level k +1) do begin
Fix the sort order of g as the order of the
group by connected to g by an A() edge ;
Generate-Plan(
)
Make k additional copies of each level k +1 vertex ;
Connect each copy vertex with the same set of level k vertices as the
original vertex ;
Assign cost A(eij) to edge eij from the original vertex
and S(eij) to edge from the copy vertex ;
Find minimum cost matching on the transformed levels.
DBMS
1999-04-01