Golden Gate - cachemgr settings

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?

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Niall Litchfield
Oracle DBA
http://www.orawin.info

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