doc: start working on public-inbox-extindex(1) manpage

It's barely started, but I started writing this weeks ago, but
I'm still unsure about some behavioral/usability things and
hoping work on lei(1) can flush them out.

1 files changed, 84 insertions, 0 deletions

diff --git a/Documentation/public-inbox-extindex.pod b/Documentation/public-inbox-extindex.pod
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+=head1 NAME
+
+public-inbox-extindex - create and update external search indices
+
+=head1 SYNOPSIS
+
+public-inbox-extindex [OPTIONS] EXTINDEX_DIR INBOX_DIR...
+
+public-inbox-extindex [OPTIONS] [EXTINDEX_DIR] --all
+
+=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
+L<Search::Xapian> XS bindings OR the L<Xapian> SWIG bindings,
+along with L<DBD::SQLite> and L<DBI> Perl modules.
+
+=head1 OPTIONS
+
+=over
+
+=item --jobs=JOBS, -j
+
+... TODO, see L<public-inbox-index(5)>
+
+=back
+
+=head1 FILES
+
+L<public-inbox-extindex-format(5)>
+
+=head1 CONFIGURATION
+
+... TODO, see L<public-inbox-index(5)>
+
+=head1 ENVIRONMENT
+
+=over 8
+
+=item PI_CONFIG
+
+Used to override the default "~/.public-inbox/config" value.
+
+=item XAPIAN_FLUSH_THRESHOLD
+
+The number of documents to update before committing changes to
+disk.  This environment is handled directly by Xapian, refer to
+Xapian API documentation for more details.
+
+Setting C<XAPIAN_FLUSH_THRESHOLD> or
+C<publicinbox.indexBatchSize> for a large C<--reindex> may cause
+L<public-inbox-mda(1)>, L<public-inbox-learn(1)> and
+L<public-inbox-watch(1)> tasks to wait long and unpredictable
+periods of time during C<--reindex>.
+
+Default: none, uses C<publicinbox.indexBatchSize>
+
+=back
+
+=head1 UPGRADING
+
+Occasionally, public-inbox will update it's schema version and
+require a full index by running this command.
+
+=head1 CONTACT
+
+Feedback welcome via plain-text mail to L<mailto:meta@public-inbox.org>
+
+The mail archives are hosted at L<https://public-inbox.org/meta/>
+and L<http://hjrcffqmbrq6wope.onion/meta/>
+
+=head1 COPYRIGHT
+
+Copyright 2021 all contributors L<mailto:meta@public-inbox.org>
+
+License: AGPL-3.0+ L<https://www.gnu.org/licenses/agpl-3.0.txt>
+
+=head1 SEE ALSO
+
+L<Search::Xapian>, L<DBD::SQLite>