db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From dag.wan...@oracle.com (Dag H. Wanvik)
Subject Re: [jira] Commented: (DERBY-4908) Instability in CheckConstraintTest.testBuiltInFunctions
Date Fri, 19 Nov 2010 21:27:28 GMT
Bryan Pendleton <bpendleton.derby@gmail.com> writes:

<good explanation of optimizer workings>

Doesn't this still leave the question why the test is unstable?: What
could make the optimizer choice vary from test run to test run? I can
think of the maximum time the optimizer would spend before it gives up
looking for further plans, and that this could lead to different choice
depending on machine performance, load etc. Does this test involve a
large join? 

If not, what else could make the optimizer choice non-predictable?

Dag


Mime
View raw message