Re: Lot of Latch Free and Enqueue Hash Chain Wait Events

Hi,

Huge Memory Configured, I don't have access to OS level as this is an AWS RDS ( Sadly!) and not sure on other methods to check the same.

CPU Usage is at over 90% during that period.

SGA is sized at 40 GB, with shared pool at 5 GB and DB_CACHE_SIZE at 20 GB. PGA_AGGREGATE_TARGET - 40 GB. I don't think there was any swapping during that time.

No resource management was configured.

[image: Inline image 1]

On Tue, Oct 3, 2017 at 11:52 AM, Hans Forbrich <fuzzy.graybeard_at_gmail.com> wrote:

> Excellent information.
>
> Huge memory configured?
> Size of SGA?
> Any other load on system such as other database instances or non-DB work?
> Any information about CPU usage at time of incident?
> Any indication that you are driving into swapping?
> Any resource management in the DB configured?
>
> Others may have additional questions ...
> /Hans
>
>
>
> On 2017-10-03 12:39 PM, Ravi Teja Bellamkonda wrote:
>
> Hi Hans,
>
> Platform_Name - Linux x86 64-bit
> cpu_count - 40
> Host Memory - 160 GB
>
> Version Details:
>
> Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit
> Production
> PL/SQL Release 11.2.0.4.0 - Production
> "CORE 11.2.0.4.0 Production"
> TNS for Linux: Version 11.2.0.4.0 - Production
> NLSRTL Version 11.2.0.4.0 - Production
>
> Patch:
>
> PSU PSU 11.2.0.4.160119
>
> 4000 - 5000 VUsers.
>
> On Tue, Oct 3, 2017 at 11:33 AM, Hans Forbrich <fuzzy.graybeard_at_gmail.com>
> wrote:
>
>> Now would be a good time to provide some details:
>>
>> - Operating System & relevant details (version, memory)?
>> - Oracle Version, Edition, Patch level?
>> - Some load information (Users/Threads/Connection, Connection style) ?
>>
>> to start.
>> /Hans
>>
>>
>> On 2017-10-03 9:47 AM, Ravi Teja Bellamkonda wrote:
>>
>> Hi,
>>
>> I started my analysis based on the AWR Report, which is stating high wait
>> events on Latch Free.
>>
>> [image: Inline image 1]
>>
>> On Tue, Oct 3, 2017 at 8:08 AM, bhavani d <bhavani021_at_gmail.com> wrote:
>>
>>> Dont assume.
>>>
>>> Just take the AWR report and verify in top wait event section
>>>
>>> On Tue, Oct 3, 2017 at 10:59 AM, Ravi Teja Bellamkonda <
>>> raviteja.bellamkonda7_at_gmail.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> Thanks for your time.
>>>>
>>>> Some slowness was reported on the database calls, but that could be
>>>> because of the load on the database.
>>>>
>>>> I am assuming that there might be a problem based on the observations.
>>>>
>>>> Thanks.
>>>>
>>>>
>>>> On Oct 3, 2017 7:55 AM, "Hans Forbrich" <fuzzy.graybeard_at_gmail.com>
>>>> wrote:
>>>>
>>>> Are you actually experiencing a problem? Or are you assuming there is
>>>> a problem because of your observations?
>>>>
>>>> /Hans
>>>>
>>>>
>>>> On 2017-10-03 8:38 AM, Ravi Teja Bellamkonda wrote:
>>>>
>>>> Hi List,
>>>>
>>>> First of all, thank you for all the time and support.
>>>>
>>>> Problem Statement is that under load we are observing a lot of Latch
>>>> Free wait events which are followed by Enqueue Hash Chains.
>>>> ...
>>>>
>>>> --
>>>> Thanks & Regards,
>>>> Ravi Teja Bellamkonda
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Thanks,
>>> Bhavani Prasad.
>>>
>>
>>
>>
>> --
>> Thanks & Regards,
>> Ravi Teja Bellamkonda
>> Ph: (816)-905-7577 <%28816%29%20905-7577>.
>>
>>
>>
>
>
> --
> Thanks & Regards,
> Ravi Teja Bellamkonda
> Ph: (816)-905-7577 <(816)%20905-7577>.
>
>
>

-- 
Thanks & Regards,
Ravi Teja Bellamkonda
Ph: (816)-905-7577.









--
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