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From Apache Wiki <wikidi...@apache.org>
Subject [Db-derby Wiki] Update of "DerbyBug47" by JamesSynge
Date Sun, 01 Oct 2006 14:57:00 GMT
Dear Wiki user,

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The following page has been changed by JamesSynge:
http://wiki.apache.org/db-derby/DerbyBug47

------------------------------------------------------------------------------
  "Query optimizer should not make poor choices when optimizing IN and WHERE clauses",
  focuses on the same issue.
  
- I attached a program to Derby Bug 47, Derby47PerformanceTest.java, that evaluates
+ I attached a program to Derby Bug 47, {{{Derby47PerformanceTest.java}}}, that evaluates
  a number of different SELECT statements that achieve the same result as evaluating:
  
  {{{ SELECT * FROM someTable WHERE aNonUniqueColumn IN (?, ?, ..., ?) }}}
@@ -31, +31 @@

  Attached to this page are two optimizer traces:
  
  {{{literals-10-trace.txt}}} for 10 parameters using the Literals strategy.
+ 
  {{{markers-10-trace.txt}}} for 10 parameters using the Markers strategy.
  
  What is most interesting is how the cost estimate for Markers is so wrong

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