SNMP Alerts on creating objects and their status on LTM

There are two ways to employ HSL for logging: 1. use an iRule; 2. use a Request Logging Profile. With an iRule, what is logged and when is entirely dependent on the logic of the rule itself.

I suspect, from your reply, that you are using a Request Logging Profile. More information is available here:

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/bigip-external-monitoring-implementations-11-5-0/1.htmlconceptid

If Request logging is enabled on a custom profile, and the profile is applied to a Virtual Server, then all requests through that Virtual Server will be logged. The specific fields logged is configurable in the profile as described above.