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From Apache Wiki <wikidi...@apache.org>
Subject [Db-derby Wiki] Trivial Update of "JoinOrderPermutations" by Army
Date Tue, 07 Nov 2006 22:49:46 GMT
Dear Wiki user,

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The following page has been changed by Army:
http://wiki.apache.org/db-derby/JoinOrderPermutations

------------------------------------------------------------------------------
  
    - costPermutation()
  
- This page describes the general flow of code as it occurs when a class such as !SelectNode
or !TableOperatorNode calls the getNextPermutation() method of an !OptimizerImpl.
+ This page describes the general flow of code as it occurs when a class such as !SelectNode
or !TableOperatorNode calls the getNextPermutation() method of an !OptimizerImpl.  The expectation
is that such a call will occur as part of a block of code similar to the following (copied
from !SelectNode.optimize()):
+ 
+ {{{
+ /* Optimize this SelectNode */
+ while (optimizer.getNextPermutation())
+ {
+     while (optimizer.getNextDecoratedPermutation())
+     {
+         optimizer.costPermutation();
+     }
+ }
+ }}}
  
  == In Short ==
  

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