Posted by Just a quick note for anyone upgrading Apex on their systems.
The installation (into a non-multitenant 12.1.0.2 instance) went through with no problems, but tracing the installation suggests it will flush the shared pool 6 times during installation/upgrade.
That might have some impact on other applications/sessions running on that database, so best to find a quiet time to do it.
Learning is not a spectator sport 
Thanks Connor,
I think I’ll wait until we have some scheduled downtime before doing the other database. 🙂
Mark
Connor,
I can assert that there is *nothing* in APEX which directly flushes the shared pool. Why would it? There are some procedures invoked in the SYS.DBMS_REGISTRY package during APEX installation which may cause the equivalent of a recompile of all invalid database objects, but I’m not aware of those procedures flushing the shared pool.
If you have evidence of the shared pool being flushed 6 times during an APEX installation, could you please share the call stack and/or reason for this suspected flush of the shared pool?
Thanks.
Joel