=head1 SYNOPSIS
-public-inbox-index GIT_DIR
+public-inbox-index [OPTIONS] GIT_DIR
=head1 DESCRIPTION
automatically maintain them.
Running this manually to update indices is only required if
-relying on L<git-fetch(1)> to mirror an existing public-inbox.
+relying on L<git-fetch(1)> to mirror an existing public-inbox;
+or if upgrading to a new version of public-inbox using
+the C<--reindex> option.
Having a search and article number database is essential to
running the NNTP interface, and strongly recommended for the
HTTP interface as it provides thread grouping in addition
to normal search functionality.
+=head1 OPTIONS
+
+=over
+
+=item --reindex
+
+Forces a search engine re-index of all messages in the
+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.
+
+This does not touch the NNTP article number database.
+
+=back
+
=head1 FILES
All public-inbox-specific files are contained within the
commands (e.g. L<xapian-compact(1)>) is not recommended unless
the list is no longer active.
+=over
+
=item $GIT_DIR/public-inbox/msgmap.sqlite3
The stable NNTP article number to Message-ID mapping is
URLs containing long Message-IDs.
Avoid removing this file and regenerating it; it may cause
-existing NNTP readers to lose sync and miss (or duplicate)
+existing NNTP readers to lose sync and miss (or see duplicate)
messages.
This file is relatively small, and typically less than 5%
requested by NNTP clients.
This directory is large, often two to three times the size of
-the objects stored in a packed git repository.
+the objects stored in a packed git repository. Using the
+C<--reindex> option makes it larger, still.
+
+=back
=head1 ENVIRONMENT