Oracle Goldengate Issue OGG-00664 OCI Error during OCIServerAttach (status = 12547-ORA- 12547: TNS:lost contact)

 I have recently encountered this issue

OGG-00664 OCI Error during OCIServerAttach (status = 12547-ORA- 12547: TNS:lost contact)

After doing some research, tried several approach, finally found a solution that worked for me

Approaches I tried that didn't work for me but seems to work for some people:

I have also listed the approaches in the order I tried them as sometimes some configuration we applied does help to achieve our resolution in the end. 

1. I noticed the os user I use to log into ggsci does not belong to the group oinstall which is the group that owns the oracle binary, so basically run the following, note that oragg is the os username that I use to run my ggsci

usermod -a -G oinstall oragg

2. Add the following lines the prm files

SETENV (TNS_ADMIN="<your oralce home>/network/admin")

SETENV (ORACLE_SID='<your oracle sid>')

SETENV (ORACLE_HOME="<your oracle home>")

I also did try (NOTE: my thought process was I don't need the old data, if you do need the old data, DON'T RUN THIS)

alter <extract process or replicat process>, begin now

so all of the above don't work, I still see the same error in the log. 

so I made one more modification to the prm files

ggsci> edit param <process>

used to be:

userid <gg user>, password <gg password>

changed to:

userid <gg user>@<oracle sid>, password <gg password>

This fixes my problem. If you are reading this, hope this helps! Enjoy!