Changeset 61001

Timestamp:

10/21/2025 02:48:53 AM (4 months ago)

Author:

desrosj

Message:

Upgrade/Install: Indicate use of MyISAM storage engine in upgrade check.

In MySQL 5.5.5, the default storage engine was changed from MyISAM to InnoDB. While still available, usage of MyISAM has been discouraged since and is considered legacy due to the lack of support for more modern feature.

The percentage of WordPress sites with MyISAM tables in the wild is currently unknown. This change adds a field to upgrade checks that includes a list of tables using MyISAM to help make more informed decisions about database features in the future.

Props johnjamesjacoby, johnbillion, dd32, desrosj, mukesh27.
Fixes #63640.

File:

• trunk/src/wp-includes/update.php (modified) (2 diffs)

trunk/src/wp-includes/update.php

@@ -107 +107 @@
         'multisite_enabled'  => $multisite_enabled,
         'initial_db_version' => get_site_option( 'initial_db_version' ),
+        'myisam_tables'      => array(),
         'extensions'         => array_combine( $extensions, array_map( 'phpversion', $extensions ) ),
         'platform_flags'     => array(
@@ -114 +115 @@
         'image_support'      => array(),
     );
+
+    // Check for default tables using the MyISAM engine.
+    $table_names   = implode( "','", $wpdb->tables() );
+    $myisam_tables = $wpdb->get_results(
+        $wpdb->prepare(
+            // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- This query cannot use interpolation.
+            "SELECT TABLE_NAME FROM information_schema.TABLES WHERE TABLE_SCHEMA = %s AND TABLE_NAME IN ('$table_names') AND ENGINE = %s;",
+            DB_NAME,
+            'MyISAM'
+        ),
+        OBJECT_K
+    );
+
+    if ( ! empty( $myisam_tables ) ) {
+        $all_unprefixed_tables = $wpdb->tables( 'all', false );
+
+        // Including the table prefix is not necessary.
+        $unprefixed_myisam_tables = array_reduce(
+            array_keys( $myisam_tables ),
+            function ( $carry, $prefixed_myisam_table ) use ( $all_unprefixed_tables ) {
+                foreach ( $all_unprefixed_tables as $unprefixed ) {
+                    if ( str_ends_with( $prefixed_myisam_table, $unprefixed ) ) {
+                        $carry[] = $unprefixed;
+                        break;
+                    }
+                }
+                return $carry;
+            },
+            array()
+        );
+
+        $query['myisam_tables'] = $unprefixed_myisam_tables;
+    }
 
     if ( function_exists( 'gd_info' ) ) {