CORRECTION: After I published this blog post saying “April 2019” my fellow support colleagues changed the alert to “June 2019”. Just saying … the topic itself is still the same.
Simon Pane from Pythian talked to me at OUGN (Oracle User Group Norway) Conference about a recently released alert in MyOracle Support saying “Databases need to be patched to a minimum before June 2019“. He was curious if I know more details. I did some investigation but shortly afterward the MOS Note got updated as well. So here’s a quick summary of things you should be aware of – but most people won’t be affected I’d guess.
Databases need to be patched to a minimum before June 2019
We released MOS Note 2361478.1 – Oracle Databases Need to be Patched to a Minimum Patchset/PSU/RU level before June 2019 mid of February 2018 as an ALERT. Oracle Supported updated it a few days ago.
The alert refers to an SCN issue which came up a while ago. The system change number (SCN) is a logical, internal timestamp used by the Oracle Database. SCNs order events that occur within the database, which is necessary to satisfy the ACID properties of a transaction. The database uses SCNs to query and track changes.
When you have databases connected to each other via database links, you must ensure that the participating databases are on a certain patch level. The correct patch level will ensure proper functioning of database links.
These database releases are patched already out-of-the-box:
- 18.104.22.168 and newer
Only if you still use databases below 22.214.171.124 make sure you patched them to the right level or higher. Please see the table matrix in MOS Note 2361478.1 and find the minimum patches for your outdated versions.
If you still have questions you may either open an SR or raise it in this forum:
Just a recommendation on the side:
There are no bug fixes and security fixes for database releases below Oracle 126.96.36.199. Therefore you should upgrade your older database anyways. I’m pretty sure you know this already 🙂
Please read on here – this is an updated and newer blog post regarding the same topic, published in February 2019:
You will find some pretty helpful notes on MyOracle Support regarding SCN Issues:
- MOS Note 2361478.1 – Oracle Databases Need to be Patched to a Minimum Patchset/PSU/RU level before April 2019
- Mandatory Patching Requirement for Database Versions below Oracle 12.2
- Frits Hoogland’s Blog Post with MANY details and insights
- MOS Note:1376995.1 – Information on the System Change Number (SCN) and how it is used in Oracle
- MOS Note:1393363.1 – Installing, Executing and Interpreting output from the “scnhealthcheck.sql” script
- MOS Note:12371955.8 – Bug 12371955 – Hot Backup can cause increased SCN growth rate leading to ORA-600  errors
- MOS Note:1376995.1 – System Change Number (SCN), Headroom, Security and Patch Information
- MOS Note:2329044.1 – SCN Issues: Checklist of Evidence to Supply
- MOS Note:1388639.1 – Evidence to collect when reporting “high SCN rate” issues to Oracle Support)