Changeset 31349 for trunk/src/wp-admin/includes/schema.php

Timestamp:

02/06/2015 04:50:19 AM (10 years ago)

Author:

pento

Message:

WPDB: If a site is using the utf8 charset, and their version of MySQL supports utf8mb4, auto-upgrade them to utf8mb4.

This patch also resizes some indexes, to allow for the 767 byte index size limit in standard MySQL installs.

See #21212

File:

• trunk/src/wp-admin/includes/schema.php (modified) (9 diffs)

trunk/src/wp-admin/includes/schema.php

@@ -44 +44 @@
     // Engage multisite if in the middle of turning it on from network.php.
     $is_multisite = is_multisite() || ( defined( 'WP_INSTALLING_NETWORK' ) && WP_INSTALLING_NETWORK );
+
+    /*
+     * Indexes have a maximum size of 767 bytes. Historically, we haven't need to be concerned about that.
+     * As of 4.2, however, we moved to utf8mb4, which uses 4 bytes per character. This means that an index which
+     * used to have room for floor(767/3) = 255 characters, now only has room for floor(767/4) = 191 characters.
+     */
+    $max_index_length = 191;
 
     // Blog specific tables.
@@ -52 +59 @@
  term_group bigint(10) NOT NULL default 0,
  PRIMARY KEY  (term_id),
- KEY slug (slug),
- KEY name (name)
+ KEY slug (slug($max_index_length)),
+ KEY name (name($max_index_length))
 ) $charset_collate;
 CREATE TABLE $wpdb->term_taxonomy (
@@ -80 +87 @@
   PRIMARY KEY  (meta_id),
   KEY comment_id (comment_id),
-  KEY meta_key (meta_key)
+  KEY meta_key (meta_key($max_index_length))
 ) $charset_collate;
 CREATE TABLE $wpdb->comments (
@@ -137 +144 @@
   PRIMARY KEY  (meta_id),
   KEY post_id (post_id),
-  KEY meta_key (meta_key)
+  KEY meta_key (meta_key($max_index_length))
 ) $charset_collate;
 CREATE TABLE $wpdb->posts (
@@ -164 +171 @@
   comment_count bigint(20) NOT NULL default '0',
   PRIMARY KEY  (ID),
-  KEY post_name (post_name),
+  KEY post_name (post_name($max_index_length)),
   KEY type_status_date (post_type,post_status,post_date,ID),
   KEY post_parent (post_parent),
@@ -214 +221 @@
   PRIMARY KEY  (umeta_id),
   KEY user_id (user_id),
-  KEY meta_key (meta_key)
+  KEY meta_key (meta_key($max_index_length))
 ) $charset_collate;\n";
 
@@ -262 +269 @@
   path varchar(100) NOT NULL default '',
   PRIMARY KEY  (id),
-  KEY domain (domain,path)
+  KEY domain (domain(140),path(51))
 ) $charset_collate;
 CREATE TABLE $wpdb->sitemeta (
@@ -270 +277 @@
   meta_value longtext,
   PRIMARY KEY  (meta_id),
-  KEY meta_key (meta_key),
+  KEY meta_key (meta_key($max_index_length)),
   KEY site_id (site_id)
 ) $charset_collate;
@@ -289 +296 @@
   KEY user_email (user_email),
   KEY user_login_email (user_login,user_email),
-  KEY domain_path (domain,path)
+  KEY domain_path (domain(140),path(51))
 ) $charset_collate;";