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Page-level SIMC

SIMC has one descriptor per tuple ... potentially inefficient.

Alternative approach: one descriptor for each data page.

Every attribute of every tuple in page contributes to descriptor.

Size of page descriptor (PD) (clearly larger than tuple descriptor):

  • use above formulae but with c.n "attributes"
E.g. n = 4, c = 64, pF = 10-3   ⇒   m ≅ 3680bits ≅ 460bytes

Typically, pages are 1..8KB  ⇒  8..64 PD/page (cPD).

E.g. m ≅ 460,   B = 8192,   cPD ≅ 17