Some troubles — especially those happening only sporadically — are not so easy to shoot and call for a deeper understanding of the matter. In the following real-world example this means: SQL*Net Tracing and some knowledge about the inner workings of the server’s operating system, particularly random number generation.
This case was suited well to demonstrate an approach to trouble-shoot connections to Oracle databases.
Sometimes it’s hard to find what you’re looking for in the Oracle documentation or on MOS if you don’t already know what exactly to search for. This happened to me while trying to find out how the method of changing the DB connection for the EM repository changed in 13c. So I thought my findings are worth sharing.
In earlier releases of Enterprise Manager (Grid Control or Cloud Control), connection settings were stored in a file named “emoms.properties”. While this file still existed on the EM 13.2 environment I was working on, there wasn’t any connection string in it.
After searching for quite a while (sifting a wealth of outdated documents), I found out there’s a specific emctl command to set the DB connection. This command already exists since 11g where it had to be used when the repository DB was put in a RAC. Now it seems to be the only way to change the connect string, be it RAC or single instance.
Note to self:
You can export highlighted text (e.g.: SQL code) easily from Notepad++ to RTF and/or HTML using “Plugins” – “NppExport” – “…”. Voilá – there’s highlighted code in your Document, Presentation, Website, a.s.f.!
Also, this: https://sqlandplsql.com/2012/08/11/notepad-tips-and-tricks/