I am working on converting an Oracle 11g database to Oracle 12c. (Its not exactly an upgrade; basically I'm setting up a new server and importing data from the old server to the new.)
Both the original 11g database and new were more or less set up 'right out of the box' (i.e. very few tweaks were done.) The setup of the databases is as follows:
Oracle 11g 11.2.0.1.0
SGA Size: 3GB
Platform: Windows Server 2008R2 Standard (64 bit) with 8GB of memory
Oracle 12c 12.1.0.2.0
SGA Size: 6GB
Platform: Windows Server 2012 R2 (64 bit) with 16GB memory
Both systems use ASM/Grid Infrastructure. Both are stand-alone databases (and the 12c is not a pluggable DB). Both systems are running as VMs under VMware (on the same host). Data was transferred from 11g to 12c using datapump.
You would think that, given the resources of the 2 machines and improvements to Oracle itself, the Oracle12c database would be roughly the same speed, but instead we've found that the Oracle 12c database was around 10-20% slower than 11g.
First of all, has anyone ever experienced this before? (I have done some web searching and have found some people complaining about slower performance after an upgrade, but then this wasn't an upgrade but a new installation.)
Secondly, does anyone have any ideas for ways I can fix this?
(Note that there is a chance that the issues has nothing to do with the database; it could be a problem with the configuration of Windows itself. However, I am not the windows administrator and didn't have a part in setting up the VM itself. I know its not an issue with the hardware or LAN configuration though, since both VMs are on the same host.)