ORA-03135: connection lost contact in the alert log of a Primary DB

Problem:

The following error was keep coming in the alertlog of a 19c Primary DB having a standby DB:

ORA-03135: connection lost contact

 

Analysis:

The logfile contains the following error, which refers to a problem at the standby archive log dest side:

After trying to troubleshoot for long time and after sending tons of logs to Oracle Support, I figured  there was an archive destination on another standby DB was mistakenly left enabled after a DR drill to send the archivelogs to the same standby DB which was causing this issue!

Solution:

Disable all archivelog destination that send the arhicvelog to the standby DB causing the issue, and enable it only from one database (which is the primary in my case).

On the additional DR which was sending archivelogs to the same standby and causing that error:

SQL> alter system set log_archive_dest_state_4=defer;

Make sure to enable the archive destination from only one DB which is the Primary in my case:

SQL> alter system set log_archive_dest_state_4=enable;

 

DBA BUNDLE 7.2 [Septemper 2022]

 Since a while I didn't release the new version of the DBA BUNDLE, each time I promote a new feature a new feature comes to my mind which makes me delay the announcement until I promote the new feature, I was in this loop since the last release announcement in Jan this year. Still there are many new features still in development cycle will come soon! Stay tuned 😊

https://www.dropbox.com/s/le5pxctq0w6v49u/DBA_BUNDLE7.tar?dl=0

Once you click on the link, first close this Window:

Then, click on the Download button at the most upper right side of the page:

 If DBA Bundle is a new thing to you, please visit the below link to understand its functions and how it works:
http://dba-tips.blogspot.com/2014/02/oracle-database-administration-scripts.html

In case the Dropbox website is blocked in your network, or you cannot copy files directly to the server you want to operate the DBA Bundle from, then follow this small trick:

1- On the target machine, create a new empty file with name DBA_BUNDLE7.txt:
     # touch DBA_BUNDLE7.txt

 

2- Open below link and Copy its content (Ctrl+a then Ctrl+c) and paste it to DBA_BUNDLE7.txt file 

     https://gist.github.com/haballan/aa52fbb1f8e497db989f19ef046c7939

 

3- Execute this command to convert the text file to a tar file:
     # LC_ALL=C tr -cd 0-9a-fA-F < DBA_BUNDLE7.txt | xxd -r -p > DBA_BUNDLE7.tar