doc: document the reason for --no-renumber

[public-inbox.git] / Documentation / public-inbox-v2-format.pod

diff --git a/Documentation/public-inbox-v2-format.pod b/Documentation/public-inbox-v2-format.pod
index 7dfe3296363b1c5032eca127ee13e901a364a9a8..bc58074e0de56fdfe0c791fea2ed44ad1a5eef2d 100644 (file)
--- a/Documentation/public-inbox-v2-format.pod
+++ b/Documentation/public-inbox-v2-format.pod
@@ -117,6 +117,10 @@ Rotational storage devices are NOT recommended for indexing of
 large mail archives; but are fine for backup and usable for
 small instances.
 
+Our use of the L</OVERVIEW DB> requires Xapian document IDs to
+remain stable.  Thus, use of L<xapian-compact(1)> and
+L<copydatabase(8)> require the use of C<--no-renumber> switch.
+
 =head2 OVERVIEW DB
 
 Towards the end of v2 development, it became apparent Xapian did