Use LIMIT to speed EXISTS subqueries

EXISTS without LIMIT is considered harmful in many cases.  Thus, we will
apply such an explicit planner hint in SuperCat.  This reduces the runtime
of URI lookups on some records from 1.2s+ to less than 1ms.

Signed-off-by: Mike Rylander <mrylander@gmail.com>

diff --git a/Open-ILS/src/perlmods/lib/OpenILS/Application/SuperCat.pm b/Open-ILS/src/perlmods/lib/OpenILS/Application/SuperCat.pm
index 71b4b5f..dc62eee 100644 (file)
--- a/Open-ILS/src/perlmods/lib/OpenILS/Application/SuperCat.pm
+++ b/Open-ILS/src/perlmods/lib/OpenILS/Application/SuperCat.pm
@@ -398,6 +398,7 @@ sub cn_browse {
     if (@$statuses || @$copy_locations) {
         @cp_filter = (
             '-exists' => {
+                limit => 1,
                 from  => 'acp',
                                where => {
                     call_number => { '=' => { '+acn' => 'id' } },
@@ -523,6 +524,7 @@ sub cn_startwith {
     if (@$statuses || @$copy_locations) {
         @cp_filter = (
             '-exists' => {
+                limit => 1,
                 from  => 'acp',
                                where => {
                     call_number => { '=' => { '+acn' => 'id' } },
@@ -2159,7 +2161,8 @@ sub new_record_holdings {
                 call_number => { '=' => {'+acn'=>'id'} },
                 deleted => 'f',
                 circ_lib => \@ou_ids
-              }
+              },
+              limit => 1
             }
         }
     ]);
@@ -2182,6 +2185,7 @@ sub new_record_holdings {
             %subselect = (
                 owning_lib => \@uri_ou_ids,
                 '-exists'  => {
+                    limit => 1,
                     from  => { auricnm => 'auri' },
                     where => {
                         call_number => { '=' => {'+acn'=>'id'} },
@@ -2199,7 +2203,8 @@ sub new_record_holdings {
                         call_number => { '=' => {'+acn'=>'id'} },
                         deleted => 'f',
                         circ_lib => \@ou_ids
-                      }
+                      },
+                      limit => 1
                     }
                 },
                 { '-and' => [
@@ -2209,7 +2214,8 @@ sub new_record_holdings {
                         where => {
                             call_number => { '=' => {'+acn'=>'id'} },
                             '+auri' => { active => 't' }
-                        }
+                        },
+                        limit => 1
                     }}
                 ]}
             ]);
@@ -2281,7 +2287,8 @@ sub new_record_holdings {
         { owning_lib => \@ou_ids },
         { '-exists'  =>
             { from  => 'sdist',
-              where => { holding_lib => \@ou_ids }
+              where => { holding_lib => \@ou_ids },
+              limit => 1
             }
         }
     ]);