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From "Knut Anders Hatlen (Created) (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DERBY-5524) Speed up clean-up after StatementJdbc30Test.xtestMaxOpenStatementsWithQueryTimeout
Date Wed, 07 Dec 2011 13:36:40 GMT
Speed up clean-up after StatementJdbc30Test.xtestMaxOpenStatementsWithQueryTimeout
----------------------------------------------------------------------------------

                 Key: DERBY-5524
                 URL: https://issues.apache.org/jira/browse/DERBY-5524
             Project: Derby
          Issue Type: Improvement
          Components: Test
    Affects Versions: 10.9.0.0
            Reporter: Knut Anders Hatlen
            Assignee: Knut Anders Hatlen
            Priority: Minor


StatementJdbc30Test.xtestMaxOpenStatementsWithQueryTimeout takes close to four minutes in
my environment. It turns out it spends most of the time in tearDown() closing statements.

The test case opens a lot of statements (more than 16000) on the same connection and keeps
them open until the test has completed, to verify that it is possible to have that many open
statements on a single connection when a query timeout has been specified. The test case runs
with auto-commit enabled, and every call to Statement.close() in tearDown() therefore results
in an implicit commit. When committing a transaction, the engine needs to go through the list
of activations in that transaction. Since there's one activation per open statement, that
list is pretty long. Although it gets shorter for each statement that is closed, it takes
a while to get through all the statements (~16000^2/2 activations need to be checked before
all statements are closed...).

This can easily be fixed by disabling auto-commit for the test case. Since no (implicit) commit
happens during the test case itself, this doesn't change the semantics of the test case. It
will speed up the closing of the statements in tearDown() because it will no longer run 16000
implicit commits and traverse the long list of activations 16000 times.

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