From: Peter Rabbitson <ribasushi@cpan.org>
Date: Sat, 12 Dec 2009 23:21:05 +0000 (+0000)
Subject: Isolate prefetch heads using RNO with a subquery
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=6102431133d7cab3b4b5701dfc482b5c147a737a;p=dbsrgits%2FDBIx-Class-Historic.git

Isolate prefetch heads using RNO with a subquery
---

diff --git a/lib/DBIx/Class/Storage/DBI.pm b/lib/DBIx/Class/Storage/DBI.pm
index d69af71..dd8616d 100644
--- a/lib/DBIx/Class/Storage/DBI.pm
+++ b/lib/DBIx/Class/Storage/DBI.pm
@@ -1774,11 +1774,24 @@ sub _select_args {
 
   my @limit;
 
-  # see if we need to tear the prefetch apart (either limited has_many or grouped prefetch)
-  # otherwise delegate the limiting to the storage, unless software limit was requested
+  # see if we need to tear the prefetch apart otherwise delegate the limiting to the
+  # storage, unless software limit was requested
   if (
+    #limited has_many
     ( $attrs->{rows} && keys %{$attrs->{collapse}} )
        ||
+    # limited prefetch with RNO subqueries
+    (
+      $attrs->{rows}
+        &&
+      $sql_maker->limit_dialect eq 'RowNumberOver'
+        &&
+      $attrs->{_prefetch_select}
+        &&
+      @{$attrs->{_prefetch_select}}
+    )
+      ||
+    # grouped prefetch
     ( $attrs->{group_by}
         &&
       @{$attrs->{group_by}}
@@ -1788,7 +1801,6 @@ sub _select_args {
       @{$attrs->{_prefetch_select}}
     )
   ) {
-
     ($ident, $select, $where, $attrs)
       = $self->_adjust_select_args_for_complex_prefetch ($ident, $select, $where, $attrs);
   }