Extractions - Performance issues

Hello,

I am extracting data from a ServiceNow system. Sometimes it's quick and sometimes it takes a long time. 

To the point

"Final Count: Loaded..."

everything is always ok, but for the last steps 

"Starting load incident$sys_audit to target ..."

until

"Extraction successful"

it is very different.

2022-01-11 08:59:15 INFO Extraction successful

2022-01-11 08:59:15 INFO Table incident$sys_audit loaded ..

2022-01-10 21:36:52 INFO Inserting extracted data into the Data Pool (this may take a while)

2022-01-10 21:36:52 INFO Starting load incident$sys_audit to target ...

2022-01-10 21:34:18 INFO Final Count: Loaded 5,450,395 record(s) for table incident$sys_audit

2022-01-10 21:33:53 INFO Loading 12,276 records for table incident$sys_audit...

In the best case, it takes 20 minutes and in the worst case >14 hours for extraction to be successful

What can be the reason? How can it be fixed

Thank you

Heiko