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From Kristian Waagan <Kristian.Waa...@Sun.COM>
Subject Re: IndexOutOfBoundsException from client driver during getBlob
Date Thu, 06 Nov 2008 12:37:12 GMT
Daniel Noll wrote:
> Kristian Waagan wrote:
>> I haven't been able to obtain incorrect values, but I've been able to 
>> obtain the same locator value twice (on a multiprocessor machine and 
>> a slightly hacked Derby). It would help us a lot if we could 
>> instrument Derby to log the locator values that cause the error 
>> happening in your environment.
>> Also, on what kind of machine and operation system are you observing 
>> the error?
>
> Desktop is: Windows 2003 x86, 4 CPUs, 4GB RAM
> Server is: Windows 2003 x86, 4 CPUs, 4GB RAM
>
> Given that the information is so similar between the two, they might 
> be running on the same computer.
>
> As for reproducibility, I'm unable to reproduce it here at all, and 
> the end user only had it happen once so far.  But when it happened, it 
> apparently continued to happen for all subsequent BLOB retrievals for 
> a while, and then "fixed itself".
>
> Each of these BLOB retrievals are being done in a separate 
> transaction, which makes that last claim even more perplexing, unless 
> the client reconnected in the meantime and we simply weren't told.

Daniel,

Thanks for the information.
I feel we have too little information to create a fix - we don't even 
know what the real problem is.
The locator values are drawn from a counter, and there is a counter for 
each (root) connection. I'm having trouble understanding how we could 
get concurrency issues in this case.
Also, I think the error you are seeing suggests an invalid locator 
value, not a duplicate value.

Anything special about your network server setup? (time-slicing, 
statement caching, connection pooling)

My suggestion is to wait for a while and see if it happens again, or see 
if anyone else has suggestions.


regards,
-- 
Kristian

>
> Daniel
>


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