From 4d26fcd73702c9f3813224ef9c112ee6971e0424 Mon Sep 17 00:00:00 2001
From: Damyon Wiese <damyon@moodle.com>
Date: Tue, 6 Jun 2017 13:57:16 +0800
Subject: [PATCH] MDL-58136 cache: Add a course completion cache

The last change added 1 db read per course per page which is not OK. Add a cache to compensate.
---
 completion/completion_completion.php | 26 +++++++++++++++++++++++---
 lang/en/cache.php                    |  3 ++-
 lib/completionlib.php                |  2 ++
 lib/db/caches.php                    | 10 ++++++++++
 version.php                          |  2 +-
 5 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/completion/completion_completion.php b/completion/completion_completion.php
index 4e0a33c4436..04b05c4abf7 100644
--- a/completion/completion_completion.php
+++ b/completion/completion_completion.php
@@ -74,7 +74,16 @@ class completion_completion extends data_object {
      * @return data_object instance of data_object or false if none found.
      */
     public static function fetch($params) {
-        return self::fetch_helper('course_completions', __CLASS__, $params);
+        $cache = cache::make('core', 'coursecompletion');
+
+        $key = $params['userid'] . '_' . $params['course'];
+        if ($hit = $cache->get($key)) {
+            return $hit['value'];
+        }
+
+        $tocache = self::fetch_helper('course_completions', __CLASS__, $params);
+        $cache->set($key, ['value' => $tocache]);
+        return $tocache;
     }
 
     /**
@@ -179,9 +188,10 @@ class completion_completion extends data_object {
             $this->timeenrolled = 0;
         }
 
+        $result = false;
         // Save record
         if ($this->id) {
-            return $this->update();
+            $result = $this->update();
         } else {
             // Make sure reaggregate field is not null
             if (!$this->reaggregate) {
@@ -193,7 +203,17 @@ class completion_completion extends data_object {
                 $this->timestarted = 0;
             }
 
-            return $this->insert();
+            $result = $this->insert();
         }
+
+        if ($result) {
+            // Update the cached record.
+            $cache = cache::make('core', 'coursecompletion');
+            $data = $this->get_record_data();
+            $key = $data->userid . '_' . $data->course;
+            $cache->set($key, ['value' => $data]);
+        }
+
+        return $result;
     }
 }
diff --git a/lang/en/cache.php b/lang/en/cache.php
index b97ae2b189e..84bcf617947 100644
--- a/lang/en/cache.php
+++ b/lang/en/cache.php
@@ -41,8 +41,9 @@ $string['cachedef_capabilities'] = 'System capabilities list';
 $string['cachedef_config'] = 'Config settings';
 $string['cachedef_coursecat'] = 'Course categories lists for particular user';
 $string['cachedef_coursecatrecords'] = 'Course categories records';
-$string['cachedef_coursecontacts'] = 'List of course contacts';
 $string['cachedef_coursecattree'] = 'Course categories tree';
+$string['cachedef_coursecompletion'] = 'Course completion status';
+$string['cachedef_coursecontacts'] = 'List of course contacts';
 $string['cachedef_coursemodinfo'] = 'Accumulated information about modules and sections for each course';
 $string['cachedef_completion'] = 'Activity completion status';
 $string['cachedef_databasemeta'] = 'Database meta information';
diff --git a/lib/completionlib.php b/lib/completionlib.php
index 80c854242db..c32ad4c4bfe 100644
--- a/lib/completionlib.php
+++ b/lib/completionlib.php
@@ -769,6 +769,7 @@ class completion_info {
 
         // Difficult to find affected users, just purge all completion cache.
         cache::make('core', 'completion')->purge();
+        cache::make('core', 'coursecompletion')->purge();
     }
 
     /**
@@ -820,6 +821,7 @@ class completion_info {
 
         // Difficult to find affected users, just purge all completion cache.
         cache::make('core', 'completion')->purge();
+        cache::make('core', 'coursecompletion')->purge();
     }
 
     /**
diff --git a/lib/db/caches.php b/lib/db/caches.php
index 9a8e9f24e5d..e75a61d4922 100644
--- a/lib/db/caches.php
+++ b/lib/db/caches.php
@@ -229,6 +229,16 @@ $definitions = array(
         'staticaccelerationsize' => 2, // Should be current course and site course.
     ),
 
+    // Used to cache course completion status.
+    'coursecompletion' => array(
+        'mode' => cache_store::MODE_APPLICATION,
+        'simplekeys' => true,
+        'simpledata' => true,
+        'ttl' => 3600,
+        'staticacceleration' => true,
+        'staticaccelerationsize' => 30, // Will be users list of current courses in nav.
+    ),
+
     // A simple cache that stores whether a user can expand a course in the navigation.
     // The key is the course ID and the value will either be 1 or 0 (cast to bool).
     // The cache isn't always up to date, it should only ever be used to save a costly call to
diff --git a/version.php b/version.php
index 2ac0f1afee1..171ef5071de 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2016120503.07;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2016120503.08;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.