cayenne-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Christian Mittendorf <christian.mittend...@freenet.de>
Subject Re: Duplicate Key Problem
Date Wed, 12 Jul 2006 21:55:50 GMT
Hmm... we had experienced some OutOfMemoryExceptions during the last  
weeks. That
would be an explanation, wouldn't it? However, I can't remember one  
on that day. I'll have
a closer look at the log file tomorrow.

Christian

Am 12.07.2006 um 23:40 schrieb Andrus Adamchik:

> Hmm.. MySQLPkGenerator runs "UNLOCK" in the finally block. Of  
> course if the connection goes down or something else equally bad  
> happens during unlock, then you can end up locking the table. I'll  
> be curious to know what exactly happened, as we may improve the  
> unlock reliability as a result.
>
> Andrus
>
>
> On Jul 12, 2006, at 5:29 PM, Christian Mittendorf wrote:
>
>> Yes, all of our applications on this database are cayenne based.
>> I will have a look at the logs tomorrow and see if I can find some
>> other exceptions...
>>
>> Thanks,
>> Christian
>>
>> Am 12.07.2006 um 19:56 schrieb Gentry, Michael ((Contractor)):
>>
>>> These could be related, then.  I know the MySQL adapter has to  
>>> lock the
>>> auto_pk_support table to generate keys and perhaps something  
>>> happened to
>>> leave the table locked.  Did you see any other exceptions?
>>>
>>> Also, you said you have multiple applications hitting the same  
>>> database.
>>> Are all of these applications Cayenne-based?
>>>
>>> Thanks,
>>>
>>> /dev/mrg
>>>
>>>
>>> -----Original Message-----
>>> From: Christian Mittendorf [mailto:christian.mittendorf@freenet.de]
>>> Sent: Wednesday, July 12, 2006 1:50 PM
>>> To: cayenne-user@incubator.apache.org
>>> Subject: Re: Duplicate Key Problem
>>>
>>>
>>> We don't use the autoincrement from MySQL.
>>>
>>> Am 12.07.2006 um 16:35 schrieb Gentry, Michael ((Contractor)):
>>>
>>>> Are you using MySQL's autoincrement feature for the PKs or the
>>>> auto_pk_support table from Cayenne?
>>>>
>>>> -----Original Message-----
>>>> From: Christian Mittendorf [mailto:christian.mittendorf@freenet.de]
>>>> Sent: Wednesday, July 12, 2006 4:29 AM
>>>> To: cayenne-user@incubator.apache.org
>>>> Subject: Duplicate Key Problem
>>>>
>>>>
>>>> Hello!
>>>>
>>>> We are running a MySQL 5.0 server using InnoDB tables for our
>>>> applications. We have multiple web applications accessing this same
>>>> database and the system is running smooth and without problems
>>>> (almost).
>>>>
>>>> But yesterday we were experiencing some strange errors. During the
>>>> afternoon some CayenneRuntimeExceptions appeared in the log file,
>>>> which were caused by:
>>>>
>>>> Caused by: java.sql.SQLException: null,  message from server:
>>>> "Duplicate entry '4353880' for key 1"
>>>>
>>>> A bit later other CayenneRuntimeException appeared. For those
>>>> exceptions the cause was:
>>>>
>>>> Caused by: java.sql.SQLException: Deadlock found when trying to get
>>>> lock; Try restarting transaction,  message from server: "Lock wait
>>>> timeout exceeded; try restarting transaction"
>>>>
>>>> I'm now wondering, are both errors related to each other?
>>>>
>>>> There are, from my point of view, two possible causes for the
>>>> "Duplicate entry..." message:
>>>>
>>>> - two Insert statements on the same object, which might be possible
>>>> if the application is clustered, which our applications are not, or
>>>> - dual use of the same key in different objects
>>>>
>>>> Has anybody else experienced something like that? Are there any  
>>>> hints
>>>> what I might do to avoid such situations?
>>>>
>>>> Christian
>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>


Mime
View raw message