In HepPlanner, when a transformation happens, it will clear metadata cache for the parent of the discarded node[1]. But it doesn't clear the metadata cache for the ancestors of the parent. For example, assume we get a logical plan like
A
\
B
\
C
, if we clear the metadata cache for C after applying a rule, we should also clear the metadata cache for A and B since metadata of A and B derive from C.
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