Re: select 'x' from dual problem

Yes, am also thoght that something similar could have happening; the main app is connected to a PLC and interacting with a robot, that answer would make sense.

I'll check with the developers of the app.

Thanks

David Ramírez Reyes
Profesión: Padre de Familia y DBA en mis ratos libres Profession: Parent and DBA in my spare time

On 1 August 2016 at 12:24, Woody McKay <woody.mckay_at_gmail.com> wrote:

> I've know some old apps that issues "select 'x' from dual" every time they
> wanted to use the connection (in a connection pool) to ensure that the
> connection was hot and alive. In performance testing, this select was
> executed so much that it showed up in top 10 and consumed considerable
> resources. I talked with the Java architect and that was their solution to
> test the connection before using it... I couldn't get them to eliminate
> it, but was able to get them to not do it every single time... maybe every
> 100...
>
>
>
> On Mon, Aug 1, 2016 at 1:18 PM, David Ramírez Reyes <dramirezr_at_gmail.com>
> wrote:
>
>> Hello all,
>>
>> Windows Server 2012 STD (physical server), Oracle DB 11g R2 Std.
>>
>> Since 4 days ago, there are some cpu pick problems on the server (1 cpu 3
>> cores, 32 GB in RAM); they have been happening 2 or 3 times during the day
>> and take around 2-5 mins (the cpu picks to 100%, 99 of it used by the
>> Oracle Service).
>>
>> I checked the threads running on it with Process Explorer, but there's no
>> specific query consuming it, but many consuming less than 5% of cpu; when
>> looking at the DB to find out the SQL text, I found that the query is
>> select 'x' from dual
>>
>> AWR is disabled and no OEM console is configured (the DB was installed by
>> a vendor for Engineering team, I don't have so much information about this
>> specific setup).
>>
>> Have you ever have had problems with " select 'x' from dual" query?,
>> tried to google some but haven't found something similar.
>>
>> Thanks in advance.
>>
>> Regards
>>
>> David Ramírez Reyes
>> Profesión: Padre de Familia y DBA en mis ratos libres
>> Profession: Parent and DBA in my spare time
>>
>>
>
>
> --
> Sincerely,
>
> WoodyMcKay
>

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