lib/PublicInbox/Inbox.pm    | 15 +++++++++++++++
 lib/PublicInbox/WWW.pm      |  1 +
 lib/PublicInbox/WwwAltId.pm | 14 +-------------

diff --git a/lib/PublicInbox/Inbox.pm b/lib/PublicInbox/Inbox.pm
index 4f27d1bbb65f9aa5dee21b66aa5eb8202004f796..95ffd039fdb7390b359c66bd30be6080d280e7cc 100644
--- a/lib/PublicInbox/Inbox.pm
+++ b/lib/PublicInbox/Inbox.pm
@@ -376,4 +376,19 @@ 	}
 	git($self)->modified; # v1
 }
 
+# returns prefix => pathname mapping
+# (pathname is NOT public, but prefix is used for Xapian queries)
+sub altid_map ($) {
+	my ($self) = @_;
+	$self->{-altid_map} //= eval {
+		require PublicInbox::AltId;
+		my $altid = $self->{altid} or return {};
+		my %h = map {;
+			my $x = PublicInbox::AltId->new($self, $_);
+			"$x->{prefix}" => $x->{filename}
+		} @$altid;
+		\%h;
+	} // {};
+}
+
 1;
diff --git a/lib/PublicInbox/WWW.pm b/lib/PublicInbox/WWW.pm
index 5017f572c8947978e252463afe6df511ee4b9137..56d2c42a41cd8eafd37444e68495644f28a80388 100644
--- a/lib/PublicInbox/WWW.pm
+++ b/lib/PublicInbox/WWW.pm
@@ -170,6 +170,7 @@ }
 
 sub preload_inbox {
 	my $ibx = shift;
+	$ibx->altid_map;
 	$ibx->cloneurl;
 	$ibx->description;
 	$ibx->base_url;
diff --git a/lib/PublicInbox/WwwAltId.pm b/lib/PublicInbox/WwwAltId.pm
index 34641a926c0c4393ac08562f437c07b89d04cff6..a45d8061069e9402d8ab72c9d3af1f09895aa356 100644
--- a/lib/PublicInbox/WwwAltId.pm
+++ b/lib/PublicInbox/WwwAltId.pm
@@ -10,18 +10,6 @@ use PublicInbox::AltId;
 use PublicInbox::Spawn qw(which);
 our $sqlite3 = $ENV{SQLITE3};
 
-# returns prefix => pathname mapping
-# (pathname is NOT public, but prefix is used for Xapian queries)
-sub altid_map ($) {
-	my ($ibx) = @_;
-	my $altid = $ibx->{altid} or return {};
-	my %h = map {;
-		my $x = PublicInbox::AltId->new($ibx, $_);
-		"$x->{prefix}" => $x->{filename}
-	} @$altid;
-	\%h;
-}
-
 sub sqlite3_missing ($) {
 	PublicInbox::WwwResponse::oneshot($_[0], 501, \<<EOF);
 <pre>sqlite3 not available
@@ -51,7 +39,7 @@ # and thus not usable from DBD::SQLite.
 sub sqldump ($$) {
 	my ($ctx, $altid_pfx) = @_;
 	my $ibx = $ctx->{-inbox};
-	my $altid_map = $ibx->{-altid_map} //= altid_map($ibx);
+	my $altid_map = $ibx->altid_map;
 	my $fn = $altid_map->{$altid_pfx};
 	unless (defined $fn) {
 		return PublicInbox::WwwStream::oneshot($ctx, 404, \<<EOF);