Queries used by sqlserver probe are provided in this kb article. Running these queries requires sufficient permissions being granted to the user used in sqlserver probe.
This is described in UIM probe document: Access Prerequisites
Download the attachment available at the bottom of this KB.
Supported Versions for sqlserver probe
fg_freespace_with avail_disk and logfile_usage_with_avail_disk query
Added metric data calculation for sql server file.
check_dbalive checkpoint is not a real sql checkpoint.
If the probe successfully connects to the database, then it writes a 1 to the QOS, if the probe fails to connect to the database, it writes a 0 and sends an alarm.