It's likely a user will be low on space after running --reindex,
so recommend the use of public-inbox-compact afterwards.
And add a few more notes about using public-inbox-compact to
clarify it's for inboxes-only (and not any old Xapian DBs) that
using xapian-compact(1) directly is error-prone and likely to
break things.
=head1 NAME
-public-inbox-compact - compact Xapian DBs
+public-inbox-compact - compact Xapian DBs in an inbox
=head1 SYNOPSIS
writing while it operates.
It enforces the use of the C<--no-renumber> option of
-L<xapian-compact(1)>
+L<xapian-compact(1)> which is required to work with the
+rest of the public-inbox search code.
=head1 OPTIONS
repository. This can be used for in-place upgrades while
NNTP/HTTP server processes are utilizing the index. Keep in
mind this roughly doubles the size of the already-large
-Xapian database.
+Xapian database. Running L<public-inbox-compact(1)>
+afterwards is recommended to release free space.
This does not touch the NNTP article number database.