In the instructions for Oracles January Critical Update database administrators might be surprised to find that downtime is required for their enviornment.

Obviously one of the larger benefits of Real Application Cluster is that fact that very few situations should arrise when downtime is required. Upgrades and patches can almost always be performed on individual nodes preventing an interruption in service. January's CPU is an exception. The patch instructs administrators to recompile all views and to perform the this portion of the patch with all activity on the db quiet.

The instructions note to shutdown the enviornment and perform a startup upgrade. What the instructions fail to explain is that in a RAC enviornement you can not do a startup upgrade. You must first do the following:

startup mount;
alter system set cluster_database=false scope=spfile;
shutdown;
startup upgrade;

perform the patching as per the instructions

alter system set cluster_database=true scope=spfile;
shutdown;
startup;