How to get database's free space programmatically

InterSystems FAQ rubric

You can see the free available space for the database using the radio button "Free Space View" in Management Portal: System Operation > Databases.

And it can be obtained programmatically by the FreeSpace query of the system class SYS.Database.

Here is an example of the code (created and executed in %SYS namespace):

 /// ZISJ.mac
 Set stmt=##class(%SQL.Statement).%New()
 Set status=stmt.%PrepareClassQuery("SYS.Database","FreeSpace")
 Set rs=stmt.%Execute()
 While rs.%Next() {
   Write !
   For i=1:1:9 {
     Write rs.%GetData(i),","
   }
 }