From: Mike Rylander <mrylander@gmail.com>
Date: Tue, 12 Feb 2013 16:51:16 +0000 (-0500)
Subject: Use LIMIT to speed EXISTS subqueries
X-Git-Url: https://old-git.evergreen-ils.org/?a=commitdiff_plain;h=a605e9beb482bcdc8eee54c91b73125ebbde2f01;p=contrib%2FConifer.git

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>
Signed-off-by: Ben Shum <bshum@biblio.org>
---

diff --git a/Open-ILS/src/perlmods/lib/OpenILS/Application/SuperCat.pm b/Open-ILS/src/perlmods/lib/OpenILS/Application/SuperCat.pm
index 71b4b5f323..dc62eee9d2 100644
--- 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
             }
         }
     ]);