The SQL health check script is not SQLT. It is a completely separate utility downloaded from a different Metalink note and used in a different way. Why is it even mentioned in this book? SQLHC is considered a backup option when SQLT cannot be installed. This does not happen very often, but when it does it is usually because of site restrictions. There are many reasons for this:
Not allowed to install anything on production (security reasons).
Not allowed to install anything on production (fear of affecting production).
Installation and testing procedures take too long and you have a problem on production.
Don’t trust SQLT.
SQLT is too complicated.
Not enough space to install SQLT.