Oracle 12c Flex Cluster Installation in VirtualBox

Installing a flex cluster requires additional configuration, because GNS (Grid Naming Service) is mandatory for this new type of Oracle cluster that was introduced in Oracle Grid Infrastructure 12c. For this specific setup I have used VirtualBox with 5 virtual machines: 4-node cluster and a DHCP/DNS server VM. I don’t want to go into the details of the regular parts of the installation, this post is mainly about the GNS configuration (DHCP and DNS) and the new parts in the installation.

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INDEX SKIP SCAN not considered

This post was inspired by the below question:

http://dba.stackexchange.com/questions/64880/why-does-the-cbo-not-chose-a-lower-cost-skip-scan-without-stats

Short version: INDEX SKIP SCAN is not considered by the optimizer, when optimizer statistics are missing.
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