Re: Single stack optimistic lock exception?
Re: Single stack optimistic lock exception?
- Subject: Re: Single stack optimistic lock exception?
- From: Ken Anderson <email@hidden>
- Date: Fri, 24 Sep 2010 12:50:11 -0400
It's Oracle RAC, so yes, a cluster.
Yes, I'm REALLY sure it's single threaded.
Yes, no way for someone else to change those rows, since we audit the tables with a trigger, and they weren't modified by anything else.
The data type of the trans_id column is Number (12,0)
Ken
On Sep 24, 2010, at 12:37 PM, Miguel Arroz wrote:
> Hi!
>
> What kind of DB are you using? Is it a single server, or a cluster?
>
> Are you REALLY sure it's single threaded (although that should not make a difference, because OL doesn't work anyway ;) )?
>
> Are you REALLY sure no other app, person, alien, cosmic ray, etc, is changing the conflicting rows at the same time?
>
> (Not my suggestion, but really good point ;) ) What is the data type of the column you use for locking?
>
> Regards,
>
> Miguel Arroz
>
> On 2010/09/24, at 16:56, Ken Anderson wrote:
>
>> All,
>>
>> I have an odd problem I'm wondering if anyone else has seen before.
>>
>> I have apps that do high throughput processing of data - many times a second. It is single threaded, and uses a single EOF stack. I'm sure it's single threaded because the requests are coming in via an inbound queue, not any kind of front end.
>>
>> Every once in a while under significantly high load, I get a few optimistic lock exceptions in a row, on rows that are only being touched by this app. We audit every update, and I can look into the audit tables and verify that nothing else has modified the record except this app.
>>
>> It's almost like the snapshot has not been recorded properly before the next request is processed, so EOF thinks something else updated the value.
>>
>> Our locking is implemented on a single column, trans_id, which is updated with every save. The audit table also saves the trans_id that's responsible for moving the record into audit, and all the values match in succession.
>>
>> Has anyone had anything like this happen? Running 5.4.3 on Linux. and no... no Wonder.
>>
>> Ken _______________________________________________
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