Re: Golden Gate - cachemgr settings

From: Ls Cheng <>
Date: Wed, 14 Feb 2018 17:43:47 +0100
Message-ID: <>

Hi Chris

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


On Wed, Feb 14, 2018 at 3:40 PM, Chris Taylor <> 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 <
>> 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
>> 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

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

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