doc: document the reason for --no-renumber

We're going to need copydatabase, too

1 files changed, 2 insertions, 0 deletions

diff --git a/script/public-inbox-compact b/script/public-inbox-compact
index d22e4032..395eec37 100755
--- a/script/public-inbox-compact
+++ b/script/public-inbox-compact
@@ -51,6 +51,8 @@ sub commit_changes ($$$) {
         $im->lock_release;
         remove_tree("$old/old") or die "failed to remove $old/old: $!\n";
 }
+
+# we rely on --no-renumber to keep docids synched to NNTP
 my @compact = qw(xapian-compact --no-renumber);
 if ($v == 2) {
         require PublicInbox::V2Writable;