I recently had to move my Oracle 11g Database from a Windows 2012 R2 server to Windows 2022 server and I've been getting intermittent "Oracle Communication: Failed to connect to server or parse connection string" errors. If I reboot the server, it goes away but comes back after some time. To migrate the database, I installed the Oracle software using the default setting for a database and altered the database to mirror what I had set in the old database, then I exported the data from the old database and imported it to the new database, no problem. I got all my data and PL/SQL code (packages, procedures, and functions) and all my apps access it just fine. Eventually I will be upgrading from 11g to 23AI, but for the purposes of migration I stuck with 11g to make things easier/quicker. In any event, I getting this intermittent errors logging into the database and I'm assuming I missed a setting somewhere. If I enter the username/password a few times (3 in the most recent case) I am eventually able to log in, but this issue is popping up during data processing via my apps and is causing problems with data. Anyone have any idea what is going on? I assume I missed a setting somewhere but have no idea what. The old database was up for 8 years on Windows 2012 R2 and never had this issue.
SnapOverflow
Well, this turned out to be a minor issue. When I installed the database the default number of max connections was set to 150, apparently that isn't enough in my application environment. I set the max connections to 300 and haven't had a single instance of the error since. For those who don't know to set the max number of connections,
alter system set processes = 300 scope = spfile;and then restart the database for it to take effect.