=head1 DESCRIPTION
-FIXME: behavior not finalized It should probably write to the
-config file the first time --all is used.
-
public-inbox-extindex creates and updates an external search and
overview database used by the read-only public-inbox PSGI (HTTP),
NNTP, and IMAP interfaces. This requires either the
=item --jobs=JOBS
-... TODO, see L<public-inbox-index(5)>
+=item --no-fsync
+
+=item --dangerous
+
+=item --rethread
+
+=item --max-size SIZE
+
+=item --batch-size SIZE
+
+These switches behave as they do for L<public-inbox-index(1)>
+
+=item --all
+
+Index all C<publicinbox> entries in C<PI_CONFIG>.
+
+C<publicinbox> entries indexed by C<public-inbox-extindex> can
+have full Xapian searching abilities with the per-C<publicinbox>
+C<indexlevel> set to C<basic> and their respective Xapian
+(C<xap15> or C<xapian15>) directories removed. For multiple
+public-inboxes where cross-posting is common, this allows
+significant space savings on Xapian indices.
+
+=item --gc
+
+Perform garbage collection instead of indexing. Use this if
+inboxes are removed from the extindex, or if messages are
+purged or removed from some inboxes.
+
+=item --reindex
+
+Forces a re-index of all messages in the extindex. This can be
+used for in-place upgrades and bugfixes while read-only server
+processes are utilizing the index. Keep in mind this roughly
+doubles the size of the already-large Xapian database.
+
+The extindex locks will be released roughly every 10s to
+allow L<public-inbox-mda(1)> and L<public-inbox-watch(1)>
+processes to write to the extindex.
+
+=item --fast
+
+Used with C<--reindex>, it will only look for new and stale
+entries and not touch already-indexed messages.
=back
=head1 CONFIGURATION
-... TODO, see L<public-inbox-index(5)>
+public-inbox-extindex does not currently write to the
+L<public-inbox-config(5)> file, configuration may be entered
+manually. The extindex name of C<all> is a special case which
+corresponds to indexing C<--all> inboxes. An example for
+C<--all> is as follows:
+
+ [extindex "all"]
+ topdir = /path/to/extindex_dir
+ url = all
+ coderepo = foo
+ coderepo = bar
+
+See L<public-inbox-config(5)> for more details.
=head1 ENVIRONMENT
=head1 COPYRIGHT
-Copyright 2021 all contributors L<mailto:meta@public-inbox.org>
+Copyright all contributors L<mailto:meta@public-inbox.org>
License: AGPL-3.0+ L<https://www.gnu.org/licenses/agpl-3.0.txt>