AX 2012 Slow Down Issue

We are working on AX 2012 R3 CU9 environment. We have an ongoing issue from a few months, where the batch server (separate from main AOS) slows down over a period of few days. A job that takes 1 hour to execute takes 1.5 hours next day, then 2 hours and so on. Once we restart AX services, it is back to 1 hour. Note that data is not changing for this job by much. File size generated for that extract varies by 10-15 kb.

Other issue is related to CIL. When we try performing CIL, it doesn’t complete for more than 1 hour. Normally it takes around 15 mins. But once we restart the server, it complete within 15 mins.

We are unable to figure out root cause for both issues, however, both are resolved after a server restart. Any help in this regard is appreciated.