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From David kerber <dcker...@verizon.net>
Subject Re: Application crash after Migrate to different ESX
Date Tue, 17 May 2011 18:55:42 GMT
On 5/17/2011 2:39 PM, הילה wrote:
>>
>>>> I know that after migrate, a disconnection is expected, but in my case -
>>>> it
>>>> crashes completely, or alternately until it works (but don't know if
>> it's
>>>> stable now).
>>>
>>
>> It is not a problem, it is a feature. What is your question?
>>
>
> what is the feature here exactly?
>
>>
>> Anyway, what happens with your application if you abruptly break all
>> connections between your application and your DB? What happens with
>> your DB at the same time?
>>
>
> how can I abruptly break all connections between application and DB?
> the only way I know is take the server out of the Load balancer so no new
> users can get to the server + the LB kicks the users that are already
> connected.

Pulling the network cable at the db server would do it.


>
>>
>> I suspect that
>> a) at webapp end you will have a lot of unusable connections in the
>> pool. If you did not forget to configure validation, they will be
>> replaced by valid connections by the next time when you try to get
>> them from the pool.
>>
>
> I haven't configure validation cause in our production environment it has
> proven to be harmful (freezes application)
>
>>
>> b) at the DB end you will have a number of aborted transactions. How
>> it handles them depends on your DB.
>>
>
> How can I see the aborted transactions?
> how can I check the configuration that handles it?

That's something the db admin will have to tell you.


>
>>
>> c) at the users' end whatever they were writing to the database at
>> that moment was lost, because of b). That is why you see the
>> exceptions.
>>
>
> yeah, I know :]

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