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     'string' => array(
  35         'mode' => cache_store::MODE_APPLICATION,
  36         'simplekeys' => true,
  37         'simpledata' => true,
  38         'staticacceleration' => true,
  39         'staticaccelerationsize' => 30,
  40         'canuselocalstore' => true,
  41     ),
  42
  43     // Used to store cache of all available translations.
  44     'langmenu' => array(
  45         'mode' => cache_store::MODE_APPLICATION,
  46         'simplekeys' => true,
  47         'simpledata' => true,
  48         'staticacceleration' => true,
  49         'canuselocalstore' => 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         'simpledata' => true, // This is a read only class, so leaving references in place is safe.
  62         'staticacceleration' => true,
  63         'staticaccelerationsize' => 15
  64     ),
  65
  66     // Event invalidation cache.
  67     // This cache is used to manage event invalidation, its keys are the event names.
  68     // Whenever something is invalidated it is both purged immediately and an event record created with the timestamp.
  69     // When a new cache is initialised all timestamps are looked at and if past data is once more invalidated.
  70     // Data guarantee is required in order to ensure invalidation always occurs.
  71     // Persistence has been turned on as normally events are used for frequently used caches and this event invalidation
  72     // cache will likely be used either lots or never.
  73     'eventinvalidation' => array(
  74         'mode' => cache_store::MODE_APPLICATION,
  75         'staticacceleration' => true,
  76         'requiredataguarantee' => true,
  77         'simpledata' => true,
  78     ),
  79
  80     // Cache for question definitions. This is used by the question_bank class.
  81     // Users probably do not need to know about this cache. They will just call
  82     // question_bank::load_question.
  83     'questiondata' => array(
  84         'mode' => cache_store::MODE_APPLICATION,
  85         'simplekeys' => true, // The id of the question is used.
  86         'requiredataguarantee' => false,
  87         'datasource' => 'question_finder',
  88         'datasourcefile' => 'question/engine/bank.php',
  89     ),
  90
  91     // HTML Purifier cache
  92     // This caches the html purifier cleaned text. This is done because the text is usually cleaned once for every user
  93     // and context combo. Text caching handles caching for the combination, this cache is responsible for caching the
  94     // cleaned text which is shareable.
  95     'htmlpurifier' => array(
  96         'mode' => cache_store::MODE_APPLICATION,
  97         'canuselocalstore' => true,
  98     ),
  99
 100     // Used to store data from the config + config_plugins table in the database.
 101     // The key used is the component:
 102     //   - core for all core config settings
 103     //   - plugin component for all plugin settings.
 104     // Persistence is used because normally several settings within a script.
 105     'config' => array(
 106         'mode' => cache_store::MODE_APPLICATION,
 107         'staticacceleration' => true,
 108         'simpledata' => true
 109     ),
 110
 111     // Groupings belonging to a course.
 112     // A simple cache designed to replace $GROUPLIB_CACHE->groupings.
 113     // Items are organised by course id and are essentially course records.
 114     'groupdata' => array(
 115         'mode' => cache_store::MODE_APPLICATION,
 116         'simplekeys' => true, // The course id the groupings exist for.
 117         'simpledata' => true, // Array of stdClass objects containing only strings.
 118         'staticacceleration' => true, // Likely there will be a couple of calls to this.
 119         'staticaccelerationsize' => 2, // The original cache used 1, we've increased that to two.
 120     ),
 121
 122     // Used to cache calendar subscriptions.
 123     'calendar_subscriptions' => array(
 124         'mode' => cache_store::MODE_APPLICATION,
 125         'simplekeys' => true,
 126         'simpledata' => true,
 127         'staticacceleration' => true,
 128     ),
 129
 130     // Cache the capabilities list DB table. See get_all_capabilities in accesslib.
 131     'capabilities' => array(
 132         'mode' => cache_store::MODE_APPLICATION,
 133         'simplekeys' => true,
 134         'simpledata' => true,
 135         'staticacceleration' => true,
 136         'staticaccelerationsize' => 1,
 137         'ttl' => 3600, // Just in case.
 138     ),
 139
 140     // YUI Module cache.
 141     // This stores the YUI module metadata for Shifted YUI modules in Moodle.
 142     'yuimodules' => array(
 143         'mode' => cache_store::MODE_APPLICATION,
 144     ),
 145
 146     // Cache for the list of event observers.
 147     'observers' => array(
 148         'mode' => cache_store::MODE_APPLICATION,
 149         'simplekeys' => true,
 150         'simpledata' => true,
 151         'staticacceleration' => true,
 152         'staticaccelerationsize' => 2,
 153     ),
 154
 155     // Cache used by the {@link core_plugin_manager} class.
 156     // NOTE: this must be a shared cache.
 157     'plugin_manager' => array(
 158         'mode' => cache_store::MODE_APPLICATION,
 159         'simplekeys' => true,
 160         'simpledata' => true,
 161     ),
 162
 163     // Used to store the full tree of course categories.
 164     'coursecattree' => array(
 165         'mode' => cache_store::MODE_APPLICATION,
 166         'staticacceleration' => true,
 167         'invalidationevents' => array(
 168             'changesincoursecat',
 169         )
 170     ),
 171     // Used to store data for course categories visible to current user. Helps to browse list of categories.
 172     'coursecat' => array(
 173         'mode' => cache_store::MODE_SESSION,
 174         'invalidationevents' => array(
 175             'changesincoursecat',
 176             'changesincourse',
 177         ),
 178         'ttl' => 600,
 179     ),
 180     // Used to store data for course categories visible to current user. Helps to browse list of categories.
 181     'coursecatrecords' => array(
 182         'mode' => cache_store::MODE_REQUEST,
 183         'simplekeys' => true,
 184         'invalidationevents' => array(
 185             'changesincoursecat',
 186         ),
 187     ),
 188     // Cache course contacts for the courses.
 189     'coursecontacts' => array(
 190         'mode' => cache_store::MODE_APPLICATION,
 191         'staticacceleration' => true,
 192         'simplekeys' => true,
 193         'ttl' => 3600,
 194     ),
 195     // Used to store data for repositories to avoid repetitive DB queries within one request.
 196     'repositories' => array(
 197         'mode' => cache_store::MODE_REQUEST,
 198     ),
 199     // Used to store external badges.
 200     'externalbadges' => array(
 201         'mode' => cache_store::MODE_APPLICATION,
 202         'simplekeys' => true,
 203         'ttl' => 3600,
 204     ),
 205     // Accumulated information about course modules and sections used to print course view page (user-independed).
 206     // Used in function get_fast_modinfo(), reset in function rebuild_course_cache().
 207     'coursemodinfo' => array(
 208         'mode' => cache_store::MODE_APPLICATION,
 209         'simplekeys' => true,
 210         'canuselocalstore' => true,
 211     ),
 212     // This is the session user selections cache.
 213     // It's a special cache that is used to record user selections that should persist for the lifetime of the session.
 214     // Things such as which categories the user has expanded can be stored here.
 215     // It uses simple keys and simple data, please ensure all uses conform to those two constraints.
 216     'userselections' => array(
 217         'mode' => cache_store::MODE_SESSION,
 218         'simplekeys' => true,
 219         'simpledata' => true
 220     ),
 221
 222     // Used to cache activity completion status.
 223     'completion' => array(
 224         'mode' => cache_store::MODE_APPLICATION,
 225         'simplekeys' => true,
 226         'simpledata' => true,
 227         'ttl' => 3600,
 228         'staticacceleration' => true,
 229         'staticaccelerationsize' => 2, // Should be current course and site course.
 230     ),
 231
 232     // Used to cache course completion status.
 233     'coursecompletion' => array(
 234         'mode' => cache_store::MODE_APPLICATION,
 235         'simplekeys' => true,
 236         'simpledata' => true,
 237         'ttl' => 3600,
 238         'staticacceleration' => true,
 239         'staticaccelerationsize' => 30, // Will be users list of current courses in nav.
 240     ),
 241
 242     // A simple cache that stores whether a user can expand a course in the navigation.
 243     // The key is the course ID and the value will either be 1 or 0 (cast to bool).
 244     // The cache isn't always up to date, it should only ever be used to save a costly call to
 245     // can_access_course on the first page request a user makes.
 246     'navigation_expandcourse' => array(
 247         'mode' => cache_store::MODE_SESSION,
 248         'simplekeys' => true,
 249         'simpledata' => true
 250     ),
 251
 252     // Caches suspended userids by course.
 253     // The key is the courseid, the value is an array of user ids.
 254     'suspended_userids' => array(
 255         'mode' => cache_store::MODE_REQUEST,
 256         'simplekeys' => true,
 257         'simpledata' => true,
 258     ),
 259
 260     // Cache system-wide role definitions.
 261     'roledefs' => array(
 262         'mode' => cache_store::MODE_APPLICATION,
 263         'simplekeys' => true,
 264         'simpledata' => true,
 265         'staticacceleration' => true,
 266         'staticaccelerationsize' => 30,
 267     ),
 268
 269     // Caches plugins existing functions by function name and file.
 270     // Set static acceleration size to 5 to load a few functions.
 271     'plugin_functions' => array(
 272         'mode' => cache_store::MODE_APPLICATION,
 273         'simplekeys' => true,
 274         'simpledata' => true,
 275         'staticacceleration' => true,
 276         'staticaccelerationsize' => 5
 277     ),
 278
 279     // Caches data about tag collections and areas.
 280     'tags' => array(
 281         'mode' => cache_store::MODE_REQUEST,
 282         'simplekeys' => true,
 283         'staticacceleration' => true,
 284     ),
 285
 286     // Grade categories. Stored at session level as invalidation is very aggressive.
 287     'grade_categories' => array(
 288         'mode' => cache_store::MODE_SESSION,
 289         'simplekeys' => true,
 290         'invalidationevents' => array(
 291             'changesingradecategories',
 292         )
 293     ),
 294
 295     // Store temporary tables information.
 296     'temp_tables' => array(
 297         'mode' => cache_store::MODE_REQUEST,
 298         'simplekeys' => true,
 299         'simpledata' => true
 300     ),
 301
 302     // Caches tag index builder results.
 303     'tagindexbuilder' => array(
 304         'mode' => cache_store::MODE_SESSION,
 305         'simplekeys' => true,
 306         'simplevalues' => true,
 307         'staticacceleration' => true,
 308         'staticaccelerationsize' => 10,
 309         'ttl' => 900, // 15 minutes.
 310         'invalidationevents' => array(
 311             'resettagindexbuilder',
 312         ),
 313     ),
 314
 315     // Caches message processors.
 316     'message_processors_enabled' => array(
 317         'mode' => cache_store::MODE_APPLICATION,
 318         'simplekeys' => true,
 319         'simpledata' => true,
 320         'staticacceleration' => true,
 321         'staticaccelerationsize' => 3
 322     ),
 323
 324     // Caches the time of the last message between two users.
 325     'message_time_last_message_between_users' => array(
 326         'mode' => cache_store::MODE_APPLICATION,
 327         'simplekeys' => true, // The id of the sender and recipient is used.
 328         'simplevalues' => true,
 329         'datasource' => '\core_message\time_last_message_between_users',
 330     ),
 331
 332     // Caches font awesome icons.
 333     'fontawesomeiconmapping' => array(
 334         'mode' => cache_store::MODE_APPLICATION,
 335         'simplekeys' => true,
 336         'simpledata' => true,
 337         'staticacceleration' => true,
 338         'staticaccelerationsize' => 1
 339     ),
 340
 341     // Caches processed CSS.
 342     'postprocessedcss' => array(
 343         'mode' => cache_store::MODE_APPLICATION,
 344         'simplekeys' => true,
 345         'simpledata' => true,
 346         'staticacceleration' => false,
 347     ),
 348 );