lib/db/caches.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * Core cache definitions.
  19  *
  20  * This file is part of Moodle's cache API, affectionately called MUC.
  21  * It contains the components that are requried in order to use caching.
  22  *
  23  * @package    core
  24  * @category   cache
  25  * @copyright  2012 Sam Hemelryk
  26  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  27  */
  28
  29 $definitions = array(
  30
  31     // Used to store processed lang files.
  32     // The keys used are the revision, lang and component of the string file.
  33     // The static acceleration size has been based upon student access of the site.
  34     // NOTE: this data may be safely stored in local caches on cluster nodes.
  35     'string' => array(
  36         'mode' => cache_store::MODE_APPLICATION,
  37         'simplekeys' => true,
  38         'simpledata' => true,
  39         'staticacceleration' => true,
  40         'staticaccelerationsize' => 30
  41     ),
  42
  43     // Used to store cache of all available translations.
  44     // NOTE: this data may be safely stored in local caches on cluster nodes.
  45     'langmenu' => array(
  46         'mode' => cache_store::MODE_APPLICATION,
  47         'simplekeys' => true,
  48         'simpledata' => true,
  49         'staticacceleration' => true,
  50     ),
  51
  52     // Used to store database meta information.
  53     // The database meta information includes information about tables and there columns.
  54     // Its keys are the table names.
  55     // When creating an instance of this definition you must provide the database family that is being used.
  56     'databasemeta' => array(
  57         'mode' => cache_store::MODE_APPLICATION,
  58         'requireidentifiers' => array(
  59             'dbfamily'
  60         ),
  61         'staticacceleration' => true,
  62         'staticaccelerationsize' => 15
  63     ),
  64
  65     // Event invalidation cache.
  66     // This cache is used to manage event invalidation, its keys are the event names.
  67     // Whenever something is invalidated it is both purged immediately and an event record created with the timestamp.
  68     // When a new cache is initialised all timestamps are looked at and if past data is once more invalidated.
  69     // Data guarantee is required in order to ensure invalidation always occurs.
  70     // Persistence has been turned on as normally events are used for frequently used caches and this event invalidation
  71     // cache will likely be used either lots or never.
  72     'eventinvalidation' => array(
  73         'mode' => cache_store::MODE_APPLICATION,
  74         'staticacceleration' => true,
  75         'requiredataguarantee' => true,
  76         'simpledata' => true,
  77     ),
  78
  79     // Cache for question definitions. This is used by the question_bank class.
  80     // Users probably do not need to know about this cache. They will just call
  81     // question_bank::load_question.
  82     'questiondata' => array(
  83         'mode' => cache_store::MODE_APPLICATION,
  84         'simplekeys' => true, // The id of the question is used.
  85         'requiredataguarantee' => false,
  86         'datasource' => 'question_finder',
  87         'datasourcefile' => 'question/engine/bank.php',
  88     ),
  89
  90     // HTML Purifier cache
  91     // This caches the html purifier cleaned text. This is done because the text is usually cleaned once for every user
  92     // and context combo. Text caching handles caching for the combination, this cache is responsible for caching the
  93     // cleaned text which is shareable.
  94     // NOTE: this data may be safely stored in local caches on cluster nodes.
  95     'htmlpurifier' => array(
  96         'mode' => cache_store::MODE_APPLICATION,
  97     ),
  98
  99     // Used to store data from the config + config_plugins table in the database.
 100     // The key used is the component:
 101     //   - core for all core config settings
 102     //   - plugin component for all plugin settings.
 103     // Persistence is used because normally several settings within a script.
 104     'config' => array(
 105         'mode' => cache_store::MODE_APPLICATION,
 106         'staticacceleration' => true,
 107         'simpledata' => true
 108     ),
 109
 110     // Groupings belonging to a course.
 111     // A simple cache designed to replace $GROUPLIB_CACHE->groupings.
 112     // Items are organised by course id and are essentially course records.
 113     'groupdata' => array(
 114         'mode' => cache_store::MODE_APPLICATION,
 115         'simplekeys' => true, // The course id the groupings exist for.
 116         'simpledata' => true, // Array of stdClass objects containing only strings.
 117         'staticacceleration' => true, // Likely there will be a couple of calls to this.
 118         'staticaccelerationsize' => 2, // The original cache used 1, we've increased that to two.
 119     ),
 120
 121     // Used to cache calendar subscriptions.
 122     'calendar_subscriptions' => array(
 123         'mode' => cache_store::MODE_APPLICATION,
 124         'simplekeys' => true,
 125         'simpledata' => true,
 126         'staticacceleration' => true,
 127     ),
 128
 129     // Cache the capabilities list DB table. See get_all_capabilities in accesslib.
 130     'capabilities' => array(
 131         'mode' => cache_store::MODE_APPLICATION,
 132         'simplekeys' => true,
 133         'simpledata' => true,
 134         'staticacceleration' => true,
 135         'staticaccelerationsize' => 1,
 136         'ttl' => 3600, // Just in case.
 137     ),
 138
 139     // YUI Module cache.
 140     // This stores the YUI module metadata for Shifted YUI modules in Moodle.
 141     'yuimodules' => array(
 142         'mode' => cache_store::MODE_APPLICATION,
 143     ),
 144
 145     // Cache for the list of event observers.
 146     'observers' => array(
 147         'mode' => cache_store::MODE_APPLICATION,
 148         'simplekeys' => true,
 149         'simpledata' => true,
 150         'staticacceleration' => true,
 151         'staticaccelerationsize' => 2,
 152     ),
 153
 154     // Cache used by the {@link core_plugin_manager} class.
 155     // NOTE: this must be a shared cache.
 156     'plugin_manager' => array(
 157         'mode' => cache_store::MODE_APPLICATION,
 158         'simplekeys' => true,
 159         'simpledata' => true,
 160     ),
 161
 162     // Used to store the full tree of course categories.
 163     'coursecattree' => array(
 164         'mode' => cache_store::MODE_APPLICATION,
 165         'staticacceleration' => true,
 166         'invalidationevents' => array(
 167             'changesincoursecat',
 168         )
 169     ),
 170     // Used to store data for course categories visible to current user. Helps to browse list of categories.
 171     'coursecat' => array(
 172         'mode' => cache_store::MODE_SESSION,
 173         'invalidationevents' => array(
 174             'changesincoursecat',
 175             'changesincourse',
 176         ),
 177         'ttl' => 600,
 178     ),
 179     // Used to store data for course categories visible to current user. Helps to browse list of categories.
 180     'coursecatrecords' => array(
 181         'mode' => cache_store::MODE_REQUEST,
 182         'simplekeys' => true,
 183         'invalidationevents' => array(
 184             'changesincoursecat',
 185         ),
 186     ),
 187     // Cache course contacts for the courses.
 188     'coursecontacts' => array(
 189         'mode' => cache_store::MODE_APPLICATION,
 190         'staticacceleration' => true,
 191         'simplekeys' => true,
 192         'ttl' => 3600,
 193     ),
 194     // Used to store data for repositories to avoid repetitive DB queries within one request.
 195     'repositories' => array(
 196         'mode' => cache_store::MODE_REQUEST,
 197     ),
 198     // Used to store external badges.
 199     'externalbadges' => array(
 200         'mode' => cache_store::MODE_APPLICATION,
 201         'simplekeys' => true,
 202         'ttl' => 3600,
 203     ),
 204     // Accumulated information about course modules and sections used to print course view page (user-independed).
 205     // Used in function get_fast_modinfo(), reset in function rebuild_course_cache().
 206     'coursemodinfo' => array(
 207         'mode' => cache_store::MODE_APPLICATION,
 208         'simplekeys' => true,
 209     ),
 210     // This is the session user selections cache.
 211     // It's a special cache that is used to record user selections that should persist for the lifetime of the session.
 212     // Things such as which categories the user has expanded can be stored here.
 213     // It uses simple keys and simple data, please ensure all uses conform to those two constraints.
 214     'userselections' => array(
 215         'mode' => cache_store::MODE_SESSION,
 216         'simplekeys' => true,
 217         'simpledata' => true
 218     ),
 219
 220     // Used to cache activity completion status.
 221     'completion' => array(
 222         'mode' => cache_store::MODE_APPLICATION,
 223         'simplekeys' => true,
 224         'simpledata' => true,
 225         'ttl' => 3600,
 226         'staticacceleration' => true,
 227         'staticaccelerationsize' => 2, // Should be current course and site course.
 228     ),
 229
 230     // A simple cache that stores whether a user can expand a course in the navigation.
 231     // The key is the course ID and the value will either be 1 or 0 (cast to bool).
 232     // The cache isn't always up to date, it should only ever be used to save a costly call to
 233     // can_access_course on the first page request a user makes.
 234     'navigation_expandcourse' => array(
 235         'mode' => cache_store::MODE_SESSION,
 236         'simplekeys' => true,
 237         'simpledata' => true
 238     ),
 239
 240     // Caches suspended userids by course.
 241     // The key is the courseid, the value is an array of user ids.
 242     'suspended_userids' => array(
 243         'mode' => cache_store::MODE_REQUEST,
 244         'simplekeys' => true,
 245         'simpledata' => true,
 246     ),
 247
 248     // Caches plugins existing functions by function name and file.
 249     // Set static acceleration size to 5 to load a few functions.
 250     'plugin_functions' => array(
 251         'mode' => cache_store::MODE_APPLICATION,
 252         'simplekeys' => true,
 253         'simpledata' => true,
 254         'staticacceleration' => true,
 255         'staticaccelerationsize' => 5
 256     )
 257
 258 );