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From Oyvind.Bakk...@Sun.COM
Subject Re: [jira] Updated: (DERBY-579) Query timeout set for one statement may affect other statements with the same SQL string
Date Mon, 03 Oct 2005 15:40:44 GMT
Satheesh Bandaram wrote:
> I am not exactly objecting  :-) , but it would be nice to add a test
> case to show the problem the fix is attempting to fix. I suspect the
> original issue is easy to introduce, but hard to catch.

I have made an attempt, but it is very hard to make a consistent 
reproduction of the issue. The reason is that when a statement is 
executed, the timeout value is immediately propagated (through the 
GenericPreparedStatement) to the StatementContext and the ResultSet. 
Therefore, the time window where this bug could affect other statements 
is very small. Also, this bug may only affect statements on different 
connections, since statements on the same connection may not execute 
simultaneously. As a result, in order to reproduce this issue, one needs 
to have the same statement executed simultaneously on many connections 
on a multi-cpu machine, and even then you'd probably hardly ever see it. 
By inserting a time-consuming no-op at the right spot in the engine I 
was able to reproduce it more frequently, but we cannot do that in testing.

> While we are on this topic, I noticed SetQueryTimeoutTest test takes
> around 30-40 minutes on my laptop. On one of our build machines, it
> actually runs for longer than 2 hours when the test harness actually
> kills the test. (causing the test to fail everytime) Though this is more
> of our test machine problem (it is really sloooow), taking 30-40 minutes
> for one functional test seems too long. Is there anyway the test can be
> made to run faster?

It now runs in 29 seconds on my machine, I hope that's satisfactory. :)

> Satheesh

-- 
Oyvind Bakksjo
Sun Microsystems, Database Technology Group
Trondheim, Norway
http://weblogs.java.net/blog/bakksjo/

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