config: simplify lookup* methods

[public-inbox.git] / Documentation / public-inbox-xcpdb.pod

diff --git a/Documentation/public-inbox-xcpdb.pod b/Documentation/public-inbox-xcpdb.pod
index c47500b629a3516df5a790a4a677962b5e9fc20d..a13c4efa7bedc41427041cb552afe4c77092d351 100644 (file)
--- a/Documentation/public-inbox-xcpdb.pod
+++ b/Documentation/public-inbox-xcpdb.pod
@@ -1,10 +1,10 @@
 =head1 NAME
 
-public-inbox-xcpdb - copy Xapian DBs (for format upgrades)
+public-inbox-xcpdb - upgrade Xapian DB formats
 
 =head1 SYNOPSIS
 
-       public-inbox-xcpdb INBOX_DIR
+       public-inbox-xcpdb [OPTIONS] INBOX_DIR
 
 =head1 DESCRIPTION
 
@@ -14,9 +14,38 @@ upgrading to the latest database format supported by Xapian
 recover from Xapian database modifications from
 L<public-inbox-watch(1)> or L<public-inbox-mda(1)>.
 
-This is intended for upgrading the database format used by
-Xapian.  It DOES NOT upgrade the schema used by the
-public-inbox search interface (see L<public-inbox-index(1)>).
+=head1 OPTIONS
+
+=over
+
+=item --compact
+
+In addition to performing the copy operation, run L<xapian-compact(1)>
+on each Xapian shard after copying but before finalizing it.
+Compared to the cost of copying a Xapian database, compacting a
+Xapian database takes only around 5% of the time required to copy.
+
+Compared to L<public-inbox-compact(1)>, use of this option is
+preferable for gigantic inboxes where the coarse-grained lock
+currently required for L<public-inbox-compact(1)> can cause
+the compaction to take hours at-a-time.
+
+=item --reshard=N / -R N
+
+Reshard the Xapian database on a L<v2|public-inbox-v2-format(5)>
+inbox to C<N> shards .  Since L<xapian-compact(1)> is not suitable
+for merging, users can rely on this switch to reshard the
+existing Xapian database(s) to any positive value of C<N>.
+
+This is useful in case the Xapian DB was created with too few or
+too many shards given the capabilities of the current hardware.
+
+=item --blocksize / --no-full / --fuller
+
+These options are passed directly to L<xapian-compact(1)> when
+used with C<--compact>.
+
+=back
 
 =head1 ENVIRONMENT
 
@@ -39,6 +68,12 @@ Default: 10000
 
 =head1 UPGRADING
 
+This tool is intended for admins upgrading Xapian search databases
+used by public-inbox, NOT users upgrading public-inbox itself.
+
+In particular, it DOES NOT upgrade the schema used by the
+PSGI search interface (see L<public-inbox-index(1)>).
+
 =head1 CONTACT
 
 Feedback welcome via plain-text mail to L<mailto:meta@public-inbox.org>
@@ -54,4 +89,6 @@ License: AGPL-3.0+ L<https://www.gnu.org/licenses/agpl-3.0.txt>
 
 =head1 SEE ALSO
 
-L<copydatabase(1)>, L<public-inbox-index(1)>
+L<copydatabase(1)|https://public-inbox.org/.copydatabase.1.html>,
+L<xapian-compact(1)|https://public-inbox.org/.xapian-compact.1.html>,
+L<public-inbox-index(1)|https://public-inbox.org/public-inbox-index.html>