In a previous post I talked about the Force Full DB Caching feature introduced in Oracle RDBMS release 18.104.22.168.
This feature is available in two flavours.
– Database Caching (when possible)
– Database Caching with force option.
In this blog we look at the database caching when possible. And this one is simple, as you don’t need to do anything unless you want to make use of the when possible option… to have it always, but in that case I would go for the Full Database Caching with force option.
When an operation occurs in the Database instance like creating/cloning a Pluggable database the alert.log will list a message in case “the when possible” option is not possible anymore. The below output grepped from an alert.log after a full clone of a pluggable database.
Database Characterset for PPROD is AL32UTF8
Buffer Cache Full DB Caching mode changing from FULL CACHING ENABLED to FULL CACHING DISABLED
Full DB Caching disabled: DEFAULT_CACHE_SIZE should be at least 28557 MBs bigger than current size.
As you can see from the alert.log no error or warning is provided, just an informational message. So in case you want to grep your alert.log use the term “FULL CACHING DISABLED” and check the next line to see what a proper size of the default_cache_size needs to be.