How can I get $wpdb to show MySQL warnings?

From quick look through the source it doesn’t seem like wpdb actively implements any handling for warnings (as opposed to errors). Proactively you can just ask for them as a custom query ($wpdb->get_results( ‘SHOW WARNINGS;’ ) I suppose, but implicitly they just aren’t tracked by WP core.

Unknown file php5fcgi.core

*.core files are usually generated by the linux OS when an un handled exception crashes an application, and it include (hopefully) useful deugging information that can help you analyze the cause. From the name of the file it was probably generated from a php5fcgi. But…. those files for sure should not be in your wordpress … Read more

Debug in WP backend

The warning states the issue is coming from custom code as in core WP no function as add_role_caps_to_job_agent exists. Try searching for add_role_caps_to_job_agent in wp-content, to see how this function is getting called and fix or uncomment the call. The other two notices will disappear once the first notice is solved as WP is trying … Read more