doc: document the reason for --no-renumber

[public-inbox.git] / Documentation / public-inbox-v1-format.pod

diff --git a/Documentation/public-inbox-v1-format.pod b/Documentation/public-inbox-v1-format.pod
index 2a6b8d3c6f1c07b4073b827323c3a2a47022de90..3b0e70e1fc5f68039a114062af4b3b7282c4cc87 100644 (file)
--- a/Documentation/public-inbox-v1-format.pod
+++ b/Documentation/public-inbox-v1-format.pod
@@ -134,6 +134,10 @@ Since SCHEMA_VERSION 15 and the development of the v2 format,
 the "overview" DB also exists in the xapian directory for v1
 repositories.  See L<public-inbox-v2-format(5)/OVERVIEW DB>
 
+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.
+
 =item $GIT_DIR/ssoma.index
 
 This file is no longer used or created by public-inbox, but it is