From b6c7a25d6050ea500aa63ffa00ecf72d07040bd4 Mon Sep 17 00:00:00 2001
From: Neill Magill <neill.magill@nottingham.ac.uk>
Date: Thu, 25 Jun 2020 09:11:50 +0100
Subject: [PATCH] MDL-60583 webservice: Add index to improve token lookup
 performance

Without this index every webservice call will do a full table scan
when it tries to validate a token. On a busy site with many tokens
this adds unnecessary load to the database.
---
 lib/db/install.xml |  5 ++++-
 lib/db/upgrade.php | 12 ++++++++++++
 version.php        |  2 +-
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/lib/db/install.xml b/lib/db/install.xml
index 8f91417fa6b..0e0c4f0d49d 100644
--- a/lib/db/install.xml
+++ b/lib/db/install.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<XMLDB PATH="lib/db" VERSION="20200504" COMMENT="XMLDB file for core Moodle tables"
+<XMLDB PATH="lib/db" VERSION="20200625" COMMENT="XMLDB file for core Moodle tables"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="../../lib/xmldb/xmldb.xsd"
 >
@@ -2795,6 +2795,9 @@
         <KEY NAME="contextid" TYPE="foreign" FIELDS="contextid" REFTABLE="context" REFFIELDS="id"/>
         <KEY NAME="creatorid" TYPE="foreign" FIELDS="creatorid" REFTABLE="user" REFFIELDS="id"/>
       </KEYS>
+      <INDEXES>
+        <INDEX NAME="token" UNIQUE="false" FIELDS="token" COMMENT="This index will be used anytime a token is validated."/>
+      </INDEXES>
     </TABLE>
     <TABLE NAME="blog_association" COMMENT="Associations of blog entries with courses and module instances">
       <FIELDS>
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index dcc2f48034a..977d7dfa264 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -2486,5 +2486,17 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2020061500.02);
     }
 
+    if ($oldversion < 2020062600.01) {
+        // Add index to the token field in the external_tokens table.
+        $table = new xmldb_table('external_tokens');
+        $index = new xmldb_index('token', XMLDB_INDEX_NOTUNIQUE, ['token']);
+
+        if (!$dbman->index_exists($table, $index)) {
+            $dbman->add_index($table, $index);
+        }
+
+        upgrade_main_savepoint(true, 2020062600.01);
+    }
+
     return true;
 }
diff --git a/version.php b/version.php
index 104a1392a3a..b997323d8c7 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2020062600.00;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2020062600.01;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
 $release  = '4.0dev (Build: 20200626)'; // Human-friendly version name