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Posted to ojb-user@db.apache.org by Matthias Roth <ma...@impart.ch> on 2003/12/10 20:52:16 UTC

dead lock in odmg api

Hello
I get the newest version of ojb. I tested the concurrency of ojb (odmg api)
with 4 threads
The threads makes parallel insert, updates and selects of objects.
The odmg api locks two similar object of different transaction if they try
to call an insert at
the same time. In my test, if a lock occurs, the insert function sleeps 100
ms and tries again to
insert if a lock exception is thrown (up to 100 times then brake).
In prev. Version (old 1.0.RC4 and 0.9.7) this works fine (1,2 or 3 time
lock, but then one time success).
In the newest version the object is every time locked (100 times). It is
never released if it is one time locket.

Have some one an idea what the problem is?

regards
Matthias Roth
Dipl. Ing. HTL
in Wirtschaftsinformatik

impart Software Engineering GmbH
Chasseralstrasse 13
Postfach
CH-3063 Ittigen

Phone           +41 (0)31 922 39 25
Fax             +41 (0)31 922 39 18
EMail           mailto:matthias.roth@impart.ch
Homepage        http://www.impart.ch


Re: dead lock in odmg api

Posted by Armin Waibel <ar...@code-au-lait.de>.
Hi Matthias,

I wrote a simple multithreaded locking test case and run this test
against rc4 and the upcoming rc5 both tests fail :-(
I checked in a fix for rc5 and now my test pass.
Please, could you run your test against latest CVS to see what's going 
on? Maybe this fix solve your problem too.

regards,
Armin

Armin Waibel wrote:
> Hi Matthias,
> 
> you are the second one report about a deadlock problem in ODMG.
> I will try to figure out what's going on before long.
> (before rc5 ;-))
> 
> regards,
> Armin
> 
> Matthias Roth wrote:
> 
>> Hello
>> I get the newest version of ojb. I tested the concurrency of ojb (odmg 
>> api)
>> with 4 threads
>> The threads makes parallel insert, updates and selects of objects.
>> The odmg api locks two similar object of different transaction if they 
>> try
>> to call an insert at
>> the same time. In my test, if a lock occurs, the insert function 
>> sleeps 100
>> ms and tries again to
>> insert if a lock exception is thrown (up to 100 times then brake).
>> In prev. Version (old 1.0.RC4 and 0.9.7) this works fine (1,2 or 3 time
>> lock, but then one time success).
>> In the newest version the object is every time locked (100 times). It is
>> never released if it is one time locket.
>>
>> Have some one an idea what the problem is?
>>
>> regards
>> Matthias Roth
>> Dipl. Ing. HTL
>> in Wirtschaftsinformatik
>>
>> impart Software Engineering GmbH
>> Chasseralstrasse 13
>> Postfach
>> CH-3063 Ittigen
>>
>> Phone           +41 (0)31 922 39 25
>> Fax             +41 (0)31 922 39 18
>> EMail           mailto:matthias.roth@impart.ch
>> Homepage        http://www.impart.ch
>>
>>
> 
> 
> 
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Re: dead lock in odmg api

Posted by Armin Waibel <ar...@code-au-lait.de>.
Hi Matthias,

you are the second one report about a deadlock problem in ODMG.
I will try to figure out what's going on before long.
(before rc5 ;-))

regards,
Armin

Matthias Roth wrote:
> Hello
> I get the newest version of ojb. I tested the concurrency of ojb (odmg api)
> with 4 threads
> The threads makes parallel insert, updates and selects of objects.
> The odmg api locks two similar object of different transaction if they try
> to call an insert at
> the same time. In my test, if a lock occurs, the insert function sleeps 100
> ms and tries again to
> insert if a lock exception is thrown (up to 100 times then brake).
> In prev. Version (old 1.0.RC4 and 0.9.7) this works fine (1,2 or 3 time
> lock, but then one time success).
> In the newest version the object is every time locked (100 times). It is
> never released if it is one time locket.
> 
> Have some one an idea what the problem is?
> 
> regards
> Matthias Roth
> Dipl. Ing. HTL
> in Wirtschaftsinformatik
> 
> impart Software Engineering GmbH
> Chasseralstrasse 13
> Postfach
> CH-3063 Ittigen
> 
> Phone           +41 (0)31 922 39 25
> Fax             +41 (0)31 922 39 18
> EMail           mailto:matthias.roth@impart.ch
> Homepage        http://www.impart.ch
> 
> 



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