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Ideal condition for using sparse Look up
Posted: Sat Jul 22, 2006 6:26 am
by opdas
Hi All,
What would be an ideal condition for using sparse look up and when should we avoid the temtation of using it.
Posted: Sat Jul 22, 2006 2:00 pm
by ArndW
A pretty good time to think about using a sparse lookup is when your lookup contains 1 million rows and your incoming data stream contains a few hundred.
Posted: Sat Jul 22, 2006 6:29 pm
by ray.wurlod
More precisely, your main input stream can contain very many rows too, but only a small number distinct lookup key values.
The idea of a sparse lookup is to be able to avoid loading a huge reference table into either a virtual Data Set or Lookup File Set.