It might be related to Adaptive Features which are a set of capabilities that enable the optimizer to make run-time adjustments to execution plans and to adjust plans for future executions based on the results of previous executions.
Please check Mike’s Blog so you can apply the 12.2 behaviour on 12.1 DB.
Hopefully, patches 22652097 and 21171382 will be incorporated in the next database proactive bundle patch. So keep checking MOS note 1937782.1.
Check the options available to you depending on what you’re upgrading from: https://blogs.oracle.com/optimizer/entry/optimizer_adaptive_features_and_upgrading
I have never heard of this until I read patch 25433352 readme file (excerpt below):
“This patch is supported by Automatic Fix Control Persistence (FCP). Beginning with Database Proactive Bundle Patch 18.104.22.168.170418, specific optimizer patches with fix controls are provided and applied as part of the Database Proactive Bundle Patch, but these fix controls are disabled by default. If you require these optimized patches, you can query them to learn about each plan change fix. FCP is a framework that allows you the option to explicitly enable each optimizer patch using the
dbms_optim_bundle package as a post-installation step. FCP also takes care of persisting the same values of fix controls for patches which were applied as one off patches at the time of applying a Bundle Patch and are now part of Database Proactive Bundle Patch. See My Oracle Support Document 2147007.1 Automatic Fix Control Persistence with DBBP for more information about how to use FCP to enable optimizer patches provided by the Database Proactive Bundle Patch.”
Also check check MOS 1942966.1 about DBMS_OPTIM package usage.
If you get the error below:
http://public-yum.oracle.com/repo/OracleLinux/OL6/latest/x86_64/repodata/filelists.xml.gz: [Errno -1] Metadata file does not match checksum
Trying other mirror.
public_ol6_latest/primary | 39 MB 01:48
http://public-yum.oracle.com/repo/OracleLinux/OL6/latest/x86_64/repodata/primary.xml.gz: [Errno -1] Metadata file does not match checksum
Trying other mirror.
Error: failure: repodata/primary.xml.gz from public_ol6_latest: [Errno 256] No more mirrors to try.
Do not panic 🙂 Fix is simple, just:
1) Include http_caching=none in your /etc/yum.conf file
2) run yum clean metadata then
3) yum update