Re: Golden Gate - cachemgr settings

From: Ls Cheng <exriscer_at_gmail.com>
Date: Wed, 14 Feb 2018 17:43:47 +0100
Message-ID: <CAJ2-Qb8Q3qFdg-K+1zGvAwgpM=BGSOs3yxHOyO+7mdCw=HU6qg_at_mail.gmail.com>



Hi Chris

dirtmp is used as OGG swap area, when it cannot use more memory it just dump the transaction info to dirtmp.

Thanks

On Wed, Feb 14, 2018 at 3:40 PM, Chris Taylor < christopherdtaylor1994_at_gmail.com> wrote:

> Interesting that you're looking into this as I ran across a metalink note
> while investigating our GGate setup and severe lag on the EXTRACT.
>
> Goldengate Extract Process appears Stalled Doc ID: 1288165.1
>
> So, I started to set it but then reading about the parameter I became more
> confused. That doc id recommended a 16G cachemgr size for that issue.
>
> Apparently there's a relationship to cachemgr and the dirtmp area but I'm
> not sure what it is.
>
> Let us know what you find out.
>
> Chris
>
> On Wed, Feb 14, 2018 at 4:20 AM, Niall Litchfield <
> niall.litchfield_at_gmail.com> wrote:
>
>> Hi all
>>
>> We're in the process of implementing Golden Gate. We've observed that by
>> default on 64bit systems Golden Gate wants 64GB of memory for cache. From
>> https://docs.oracle.com/goldengate/1212/gg-winux/GWURF/gg_
>> parameters017.htm#GWURF413 " Sets a soft limit for the amount of virtual
>> memory (cache size) that is available for caching transaction data. On
>> 64-bit systems, the default is 64 GB "
>>
>> Reserving 64G of ram for Golden Gate seems an extraordinarily large
>> amount, especially on a system where multiple GG processes might be
>> running. Similarly allowing this memory to swap out seems to rather negate
>> the purpose of a cache :). There's a repeated warning in the docs *not
>> to control this* without contacting Oracle Support for guidance. Our
>> engagement with Oracle Support hasn't exactly been stellar - they're happy
>> to look at individual cases, but general guidance isn't really in their
>> remit.
>>
>> So, for folks out there using GG, do you set the CACHESIZE parameter to
>> control GG memory usage, if so how? Is it really on a case by case basis.
>> If not do you observe GG really using 64g ram for cache?
>>
>> --
>> Niall Litchfield
>> Oracle DBA
>> http://www.orawin.info
>>
>
>

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Received on Wed Feb 14 2018 - 17:43:47 CET

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