Re: write complete waits

From: John Thomas <jt2354_at_gmail.com>
Date: Mon, 28 Sep 2015 18:45:57 +0000
Message-ID: <CAOHpfbHdmifzAB_n=PPY1hDKZ-dPBFMn92+aD8-vn7kZnSrSZg_at_mail.gmail.com>

My understanding its that oracle processes can get on with other things but still need to hear from the AIO driver that the write competed successfully.

If that's wrong, I'd like to hear a correct description. Not in the office and on mobile so I'm just half speculating in case it helps .

Regards

JT

On Mon, 28 Sep 2015 19:41 Matt Anderson <matta576_at_gmail.com> wrote:

> Why would there be a wait event for an asynchronous write to complete?
> Isn't not waiting for completion the whole point behind asynchronous writes?
>
> Matt
>
> On Mon, Sep 28, 2015 at 12:00 PM John Thomas <jt2354_at_gmail.com> wrote:
>
>> Just the filesystem io one which defines asynchronous, direct io or etc
>> as supported by whatever platform you are on.
>>
>> AIO driver status might be another thing to check.
>>
>> Regards
>>
>> JT
>>
>> On Mon, 28 Sep 2015 18:05 Michael Calisi <oracle455_at_gmail.com> wrote:
>>
>>> No parameter changes recently? Any particular Oracle parameter you are
>>> thinking about?
>>>
>>
>>> On Mon, Sep 28, 2015 at 12:25 PM, John Thomas <jt2354_at_gmail.com> wrote:
>>>
>>>> Is that not a wait for asynchronous write completion? Haven't changed
>>>> parameters related to filesystem io or similar recently, have you?
>>>>
>>>> Regards
>>>>
>>>> JT
>>>>
>>>> On Mon, 28 Sep 2015 16:39 Michael Calisi <oracle455_at_gmail.com> wrote:
>>>>
>>>>> A new event suddenly start to appear in my Top 10 Events. Wondering
>>>>> what may be the cause and how to avoid.it Any information will be
>>>>> helpful.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Top 10 Foreground Events by Total Wait Time
>>>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>>> Tota Wait % DB
>>>>> Event Waits Time Avg(ms) time Wait
>>>>> Class
>>>>> ------------------------------ ------------ ---- ------- ------
>>>>> ----------
>>>>> DB CPU 14.5 18.1
>>>>> write complete waits 115 13.8 120204 17.3
>>>>> Configurat
>>>>>
>>>>
>>>

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Received on Mon Sep 28 2015 - 20:45:57 CEST