Bug 961789: large dependency trees with lots of resolved bugs are very slow to load

1 files changed, 15 insertions, 8 deletions

diff --git a/Bugzilla/Bug.pm b/Bugzilla/Bug.pm
index 1ba34f0a0..c3c9a2a2c 100644
--- a/Bugzilla/Bug.pm
+++ b/Bugzilla/Bug.pm
@@ -3855,17 +3855,24 @@ sub editable_bug_fields {
 # Join with bug_status and bugs tables to show bugs with open statuses first,
 # and then the others
 sub EmitDependList {
-    my ($myfield, $targetfield, $bug_id) = (@_);
+    my ($my_field, $target_field, $bug_id, $exclude_resolved) = @_;
+    my $cache = Bugzilla->request_cache->{bug_dependency_list} ||= {};
+
     my $dbh = Bugzilla->dbh;
-    my $list_ref = $dbh->selectcol_arrayref(
-          "SELECT $targetfield
+    $exclude_resolved = $exclude_resolved ? 1 : 0;
+    my $is_open_clause = $exclude_resolved ? 'AND is_open = 1' : '';
+
+    $cache->{"${target_field}_sth_$exclude_resolved"} ||= $dbh->prepare(
+          "SELECT $target_field
              FROM dependencies
-                  INNER JOIN bugs ON dependencies.$targetfield = bugs.bug_id
+                  INNER JOIN bugs ON dependencies.$target_field = bugs.bug_id
                   INNER JOIN bug_status ON bugs.bug_status = bug_status.value
-            WHERE $myfield = ?
-            ORDER BY is_open DESC, $targetfield",
-            undef, $bug_id);
-    return $list_ref;
+            WHERE $my_field = ? $is_open_clause
+            ORDER BY is_open DESC, $target_field");
+
+    return $dbh->selectcol_arrayref(
+        $cache->{"${target_field}_sth_$exclude_resolved"},
+        undef, $bug_id);
 }
 
 # Creates a lot of bug objects in the same order as the input array.