Upgrade to Oracle 12.2.0.1: Check your DEFAULT temporary tablespaces

One of the reasons why I have this blog is simply to stay in touch with smart people using Oracle and telling me about issues I haven’t seen before. Thanks to Tyler Van Vierzen I learned that an upgrade to Oracle 12.2.0.1 may alter the default local temporary tablespace. Upgrade to Oracle 12.2.0.1: Check your DEFAULT temporary tablespaces Tyler did contact me on Twitter: “Curious if you’ve seen this… Seeing new “local temp tablespace” set to SYSTEM for some users after 12.2 upgrade. But not all. No discernable pattern. Some null (so default to their temp tablespace), some set equal…

Optimizer Issue in Oracle 12.0.1.2: “Reduce Group By”

DBAs biggest fears I’d guess are Optimizer Wrong Query Results bugs as usually the optimizer does not write a message into the alert.log saying “Sorry, I was in a bad mood today …”. The Oracle Database Optimizer is a complex piece – and in Oracle 12c it delivers great performance results. Plus (my personal experience when you know what to do) it is more predictable which I like a lot when changing databases from one to another release. But due to its complexity sometimes we see issues – and sometimes it is necessary to switch off tiny little pieces until…