[PATCH] doc: flesh out public-inbox-index documentation

[Eric Wong <e@80x24.org>]

And include it into the build + website
---
 Documentation/include.mk             |  1 +
 Documentation/public-inbox-index.pod | 31 +++++++++++++++++++++++++++----
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/Documentation/include.mk b/Documentation/include.mk
index 5154d4b..542273f 100644
--- a/Documentation/include.mk
+++ b/Documentation/include.mk
@@ -21,6 +21,7 @@ m1 += public-inbox-mda
 m1 += public-inbox-httpd
 m1 += public-inbox-nntpd
 m1 += public-inbox-watch
+m1 += public-inbox-index
 m5 =
 m5 += public-inbox-config
 m7 =
diff --git a/Documentation/public-inbox-index.pod b/Documentation/public-inbox-index.pod
index 554346d..2871f0d 100644
--- a/Documentation/public-inbox-index.pod
+++ b/Documentation/public-inbox-index.pod
@@ -4,7 +4,7 @@ public-inbox-index - create and update search indices
 
 =head1 SYNOPSIS
 
-public-inbox-index GIT_DIR
+public-inbox-index [OPTIONS] GIT_DIR
 
 =head1 DESCRIPTION
 
@@ -18,13 +18,31 @@ L<public-inbox-mda(1)> and L<public-inbox-watch(1)> will
 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
@@ -33,6 +51,8 @@ grow in size as more messages are archived, so using compaction
 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 the list is no longer active.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
@@ -44,7 +64,7 @@ useful for attempting recovery from copy-paste truncations of
 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%
@@ -67,7 +87,10 @@ provides a cache of metadata and header information often
 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
 
-- 
EW