Code review comment for lp:~jjo/charms/precise/postgresql/support-no-explicit-version_and_trusty-pg93

> Trivial: 'canditate' should be 'candidate' throughout.

thanks for spotting, fixed.

>
> pg_version() makes several assumptions (e.g. that a postgresql package
> exists and that it's version matches a specific regex (which won't be
> the case if, e.g. the package grows an epoch) that are probably fine,
> but it caught my eye.

I found this the less painful way to find out which "short-version"
($major.$minor) is available.

>
> | + # expensive operation, save it
>
> What operation does this refer to? The function as a whole?

apt.Cache(), I clarified the comment there.