Re: DBA Job Functions
Date: Sat, 3 Mar 2018 00:03:06 +0300
Message-ID: <CAOVevU5Otty9yhDkAT3F61kO6RwABwoH77+ko=Lo-knOYfRZOA_at_mail.gmail.com>
Ram,
On Fri, Mar 2, 2018 at 11:45 PM, Ram Raman <veeeraman_at_gmail.com> wrote:
>
> From my experience, those views and utilities tell me where the time is
> going, but how do I figure why it is doing so many extra IOs suddenly, so
> many delays suddenly, etc. In this case the same disk subsytem was unable
> to handle a sudden burst in IO requests.
>
> One thing that came to my mind was seeing the past performance when things
> were bad for the SQLs in question. But past history was not available.
>
> On Fri, Mar 2, 2018 at 3:22 AM, Sayan Malakshinov <xt.and.r_at_gmail.com>
> wrote:
>
>> Mladen,
>>
>> You could have used the 10046 trace. That would tell you what is you
>>> application waiting for.
>>
>>
>> On recent oracle versions I wouldn't start from 10046, because in more
>> than 80% cases it's overkill and it requires more time(you need to wait end
>> of execution, otherwise you will not get row statistics) than other more
>> real-time tools, for example, Session Snapper, ASH, RTSM, v$session_event,
>> etc...
>>
>> At this point, I have to ask: have you read Cary Millsap's book?
>>
>>
>> "Optimizing Oracle Performance" by Cary and Jeff Holt? Yes, of course,
>> long time ago :)
>> Moreover, I subscribed to his blog (as to many others from this thread)
>> and some of my scripts are based on Cary's scripts.
>> So what's your point? Don't you think that it's much better to send more
>> detailed questions? Mail-list is not a telegram or twitter :D
>>
>> On Fri, Mar 2, 2018 at 10:04 AM, Mladen Gogala <gogala.mladen_at_gmail.com>
>> wrote:
>>
>>> At this point, I have to ask: have you read Cary Millsap's book?
>>>
>>> On 03/01/2018 08:48 PM, Sayan Malakshinov wrote:
>>>
>>> There are a lot of different types of problems, so it's more important
>>> to determine what information you need to troubleshoot current issue, and
>>> only after that you can choose a tool which can show it.
>>> In your case I think sqlplus+v$active_session_history (perhaps with
>>> v$segment_statistics) should be enough. For example, my script from not yet
>>> published post: https://github.com/xtender/xt_scripts/blob/master/ash/
>>> top_predicates.sql
>>> It shows top predicates from ASH for table access analysis
>>>
>>>
>>> --
>>> Mladen Gogala
>>> Database Consultant
>>> Tel: (347) 321-1217
>>>
>>>
>>
>>
>> --
>> Best regards,
>> Sayan Malakshinov
>> Oracle performance tuning engineer
>> Oracle ACE Associate
>> http://orasql.org
>>
>
>
>
> --
>
>
>
-- Best regards, Sayan Malakshinov Oracle performance tuning engineer Oracle ACE Associate http://orasql.org -- http://www.freelists.org/webpage/oracle-lReceived on Fri Mar 02 2018 - 22:03:06 CET