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From Army <qoz...@gmail.com>
Subject Re: [jira] Commented: (DERBY-47) Some possible improvements to IN optimization
Date Wed, 28 Mar 2007 23:52:57 GMT
Andrew McIntyre (JIRA) wrote:
> and since all the tests pass with or without ruleBasedOptimization set to true, 
> I'll leave that off. Not really worth investigating, since it seems to have no 
> effect on the new test.

Unless of course setting that property to true revealed an error once upon a 
time and that error was fixed, thus removing the error.  In that case setting or 
not setting the property would lead to the same behavior, which is in itself 
confirmation that whatever the old error was (if there was one) is actually fixed.

Or as a different (and more pertinent) example: setting the optimizeJoinOrder 
property to "true" (which is also the default) exposes a bug that results in an 
error--namely, DERBY-2500.  If I fix that bug (which I hope to!) then running 
the query should return the same results regardless of what optimizeJoinOrder is 
set to--i.e. optimizeJoinOrder will at that point "have no effect on the test". 
  But in the interest of regression testing we still want to make sure the query 
is run with optimizeJoinOrder=true (the default) as proof that DERBY-2500 is fixed.

Maybe something similar once existed for "ruleBasedOptimization=true"...?


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