How to identified active files/executables when using opatch to deinstall software

During a opatch rollback operation, we saw the following error message in the opatch logfile:

[Feb 19, 2023 2:29:51 PM] [INFO]    Prerequisite check "CheckActiveFilesAndExecutables" failed.
                                    The details are:


                                    Following active files/executables/libs are used by ORACLE_HOME :/sw/oracle/product/19.18
                                    /sw/oracle/product/19.18/lib/libclntsh.so.19.1

Reason:
Some processes are still using the /sw/oracle/product/19.18/lib/libclntsh.so.19.1.
Use the fuser utility with verbose output to find the process:

fuser -v /sw/oracle/product/19.18/lib/libclntsh.so.19.1
                     USER        PID ACCESS COMMAND
/sw/oracle/product/19.18/lib/libclntsh.so.19.1:
                     oracle    48439 ....m prometheus_orac
                     oracle    595787 ....m ggsci

There were two open processes using the file libclntsh.so.19.1: 1. the Golden Gate Manager 2. a utility called prometheus_oracle_exporter

Solution:

log in as the Golden Gate software owner
ggsci --> info all --> list all processes
stop mgr !

One of two processes quit its handler on the file:

 fuser -v /sw/oracle/product/19.18/lib/libclntsh.so.19.1
                     USER        PID ACCESS COMMAND
/sw/oracle/product/19.18/lib/libclntsh.so.19.1:
                     oracle    48439 ....m prometheus_orac

For the prometheus agent, we simply kill the agent, and the output from fuser now reveals that no file handlers are open:

kill 48439
fuser -v /sw/oracle/product/19.18/lib/libclntsh.so.19.1