Where does the database link SYS_HUB come from?

This blog lives a lot from customer’s feedback and updates. And these days, Nicolas Jardot from dbi-services in Switzerland sent me an email asking: Where does the database link SYS_HUB come from? And if he can delete it or if it has any deeper purpose. Neither Google nor MOS reveal a lot of useful information Where does the database link SYS_HUB come from? I took my vanilla 18.3.0 database in our hands-on lab and check: column owner format a5 column db_link format a12 column username format a12 column host format a12 select con_id, owner, db_link, username, host from cdb_db_links; CON_ID…

Oracle 12.2.0.1 RESTART: Make sure you’ve patched your Oracle 12.1.0.2 homes

This blog post title sounds a bit weird, doesn’t it? Oracle 12.2.0.1 RESTART: Make sure you’ve patched your Oracle 12.1.0.2 homes. Why the heck should you patch your 12.1.0.2 database homes upfront? Oracle 12.2.0.1 RESTART: Make sure you’ve patched your Oracle 12.1.0.2 homes Well, there’s an interesting issue happening. When you work with Oracle Grid Infrastructure, no matter if you operate a cluster or “just” use Oracle Restart, you’ll have to upgrade GI to Oracle 12.2 first before you can manage 12.2 databases with it. That’s not new. It’s a well understood rule. Now guess you operate Oracle RESTART (SIHA…