Re: NTP on linux box was ahead of 5 hrs

Any columns with DEFAULT SYSDATE would be suspect as well as far as application data goes. The app data inside the database has the potential to be really, seriously, screwed up.

Chris

On Mon, Nov 18, 2013 at 10:47 AM, Niall Litchfield < niall.litchfield_at_gmail.com> wrote:

> You likely need to understand how the application works and what you are
> worried about. This doesn't have a general answer.
>
> Making the simplified assumption that everyone is in the same timezone as
> the database server you still need to distinguish between code such as
>
> "insert into time_tab(cdate) values(:dt)" and "insert into time_tab(cdate)
> values(sysdate)" and "insert into time_tab(cdate) values('string from
> appserver')"
>
>
>
> On Mon, Nov 18, 2013 at 4:10 PM, nilesh kumar <nileshkum_at_gmail.com> wrote:
>
>> Thanks Martijn,
>>
>> Suppose this database belongs to a Banking sector, and few users perform
>> the transaction when NTP was 5 hrs ahead. And Suppose if user asks the
>> details of their transaction in that case we are in bit confusion state
>> right.
>>
>> In general I was checking with everyone, if someone has faced this kind
>> of issue and the work around they did to fix this one.
>>
>> Thanks for replying Martijn
>>
>> Thanks
>> Nilesh
>>
>> On Mon, Nov 18, 2013 at 8:10 PM, Martijn Bos <maboc_at_maboc.nl> wrote:
>>
>>> Hi,
>>>
>>> See my ideas inline.
>>>
>>> Best Regards,
>>> Martijn
>>>
>>>
>>> Best Regards,
>>> Martijn
>>>
>>>
>>> On Mon, Nov 18, 2013 at 07:03:32PM +0530, nilesh kumar wrote:
>>> > Hello All,
>>> >
>>> > NTP was running ahead of 5 hrs of normal time on Linux box.
>>> >
>>> > We have oracle database running on that server version 10g.
>>> >
>>> > Network team tried to synchronize the NTP and they synchronized the
>>> NTP on
>>> > the server.
>>> >
>>> > >From oracle database endi have few questions.
>>> >
>>> > I took a levelzero backup and all archive log backup immediately and
>>> asked
>>> > the application team to release all the conections to the database and
>>> > connection refresh so that none of the users are connected to the
>>> > database, and then bounced the db and again took a level zero backup.
>>> >
>>> > Am i missing any thing in this case that need to be taken care.
>>> >
>>> > few more question in mind:-
>>> > ----------------------------------------
>>> >
>>> > Database was running and users were connected to the database during
>>> this
>>> > issue occured, if some users committed the transactions and when NTP
>>> was 5
>>> > hrs ahead and does any inconsistency occur after the NTP was
>>> synchronized.
>>>
>>> The database ticks around scn's so, on a 'physical' level I do not
>>> expect inconsistencys.
>>> On a logical level (data-model), you may expect inconsistencys when
>>> 'sysdate' has been used to fill some rows.
>>> (Also think of RI where sysdate is used in a column)
>>>
>>> >
>>> > ----------------------------------------
>>> > This has not occured but have a question for the below conditon.
>>> > If suppose the DB would have crashed after the NTP synchronization and
>>> > backup taken last sunday level zero, till what time would we able to
>>> > recover the DB, as few archives have generated after when the NTP was
>>> 5 hrs
>>> > ahead in time.
>>> >
>>>
>>> I think that a Point In Time recovery will be a little hazardous.
>>> In this case I would try to restore to a sequence number or even a scn.
>>>
>>> I _think_ that a restore would restore to the time before the
>>> re-syncronaziation (the first time that time x appeared).
>>>
>>> > Please advise
>>> >
>>> > Thanks
>>> > Nilesh
>>> >
>>> >
>>> >
>>> > --
>>> > Thanks & Regards
>>> > Nilesh
>>> > Oracle DBA (sqlplus "/as sysdba" is my world)
>>> >
>>> > "As our circle of knowledge expands, so does the circumference of
>>> darkness
>>> > surrounding it."--Einstein
>>> > "All men die, few men ever truly live" -- Braveheart
>>> > "You can get help from teachers, but you are going to have to learn a
>>> lot
>>> > by yourself, sitting alone in a room." --Dr. Seuss
>>> > "Know me for what I do and for not what I am. Judge me for what I can
>>> do
>>> > and not for what I have done."-Unknown
>>> > "Don't walk in front of me, I may not follow. Don't walk behind me, I
>>> may
>>> > not lead. Just walk beside me and be my friend."- Albert Camus
>>> > "Never argue with an idiot. They drag you down to their level and then
>>> beat
>>> > you with experience." - Unknown
>>> >
>>> >
>>>
>>
>>
>>
>> --
>> Thanks & Regards
>> Nilesh
>> Oracle DBA (sqlplus "/as sysdba" is my world)
>>
>> "As our circle of knowledge expands, so does the circumference of
>> darkness surrounding it."--Einstein
>> "All men die, few men ever truly live" -- Braveheart
>> "You can get help from teachers, but you are going to have to learn a lot
>> by yourself, sitting alone in a room." --Dr. Seuss
>> "Know me for what I do and for not what I am. Judge me for what I can do
>> and not for what I have done."-Unknown
>> "Don't walk in front of me, I may not follow. Don't walk behind me, I may
>> not lead. Just walk beside me and be my friend."- Albert Camus
>> "Never argue with an idiot. They drag you down to their level and then
>> beat you with experience." - Unknown
>>
>
>
>
> --
> Niall Litchfield
> Oracle DBA
> http://www.orawin.info
>

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