From cdaedc195bc400c1744c3265f0e293fddd0649b2 Mon Sep 17 00:00:00 2001
From: Francesco Rivetti <oha@oha.it>
Date: Tue, 14 Feb 2017 11:13:51 +0100
Subject: [PATCH] Bug 17941 avoid scanning the full cartesian product

when a item match a borrower, there is no point in checking the
other borrowers
---
 C4/Circulation.pm | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/C4/Circulation.pm b/C4/Circulation.pm
index 330923e..c90dda2 100644
--- a/C4/Circulation.pm
+++ b/C4/Circulation.pm
@@ -2679,24 +2679,23 @@ sub CanBookBeRenewed : PureFunction {
             # can be filled with available items. We can get the union of the sets simply
             # by pushing all the elements onto an array and removing the duplicates.
             my @reservable;
-            foreach my $b (@borrowernumbers) {
-                my ($borr) = C4::Members::GetMember( borrowernumber => $b);
-                foreach my $i (@itemnumbers) {
-                    my $item = GetItem($i);
-                    if (  !IsItemOnHoldAndFound($i)
-                        && IsAvailableForItemLevelRequest( $item, $borr )
-                        && CanItemBeReserved( $b, $i ) )
-                    {
-                        push( @reservable, $i );
+            my %borrowers;
+            ITEM: foreach my $i (@itemnumbers) {
+                my $item = GetItem($i);
+                next if IsItemOnHoldAndFound($i);
+                for my $b (@borrowernumbers) {
+                    my $borr = $borrowers{$b}//= C4::Members::GetMember(borrowernumber => $_);
+                    next unless IsAvailableForItemLevelRequest($item, $borr);
+                    next unless CanItemBeReserved($b,$i);
+
+                    push @reservable;
+                    if (@reservable >= @borrowernumbers) {
+                        $resfound = 0;
+                        last ITEM;
                     }
+                    last;
                 }
             }
-
-            @reservable = uniq(@reservable);
-
-            if ( @reservable >= @borrowernumbers ) {
-                $resfound = 0;
-            }
         }
     }
     return ( 0, "on_reserve" ) if $resfound;    # '' when no hold was found
-- 
2.7.4