How do i reload the tags file from within Vim?
Is a restart necessary?
According to :help tag-binary-search, the tags file is binary (or linear) searched on each lookup, so there's no need to reload the file:
*tag-binary-search*
Vim uses binary searching in the tags file to find the desired tag quickly
(when enabled at compile time |+tag_binary|). But this only works if the
tags file was sorted on ASCII byte value. Therefore, if no match was found,
another try is done with a linear search. If you only want the linear search,
reset the 'tagbsearch' option. Or better: Sort the tags file!
Note that the binary searching is disabled when not looking for a tag with a
specific name. This happens when ignoring case and when a regular expression
is used that doesn't start with a fixed string. Tag searching can be a lot
slower then. The former can be avoided by case-fold sorting the tags file.
See 'tagbsearch' for details.