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I'm facing some problems with performance with my Oracle database running on a virtual machine with Microsoft Windows Server Enterprise 2003 with 8GB RAM.

It works pretty well after the database is initialized, but after some time it starts slowing down. I've tried to run statistics, rebuild all indexes, export and reimport the dump file, uninstalling/reinstalling Oracle, increase the sga size.. but none of these worked so far. The strangest thing is that if I import this dump into a virtual machine running Microsoft Windows Server STANDARD 2003 with 4GB RAM it works perfect without any performance issue.

Question: Is there a different configuration that must be done on Oracle or on Windows Server Enterprise 2003 to avoid this problem? I'm a not a DBA, so my point of view is that the machine with 8GB should run better than the other one, am I right?

Thanks in advance.

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Normally, yes, you are correct, but only _in general_. If your system is constructing linked lists in RAM which must be traversed you _could_ experience performance problems by increasing RAM. It's not common but neither is it unheard of. Could you try and do a test with Linux? Hmmm... Also, VMs... can you be sure that your disk config is the same? Do you have separate disk arrays for the data, OS &c.? Can you try on bare metal? It seems to me that you are not using the force young Luke, but rather flailing around trying random stuff that occurs to you. You need a scientific approach! – Vérace May 30 '14 at 9:26
To add a word - under Oracle, the scientific method means finding out where the system is spending time - that's what the Oracle Wait Interface (OWI) is for - have you looked at this? Oracle is not easy, but I think you may need to delve into the lore of the ancients (i.e. books!). Also, you don't mention 32/64 bit. – Vérace May 30 '14 at 9:28

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