Improve speed of MySQLDatabaseEditor::getForeignKeys()

The JOIN made the previous very slow.

diff --git a/wcfsetup/install/files/lib/system/database/editor/MySQLDatabaseEditor.class.php b/wcfsetup/install/files/lib/system/database/editor/MySQLDatabaseEditor.class.php
index 0f22908e5e31a4f1c4436001865fe7aa0c22f21f..ecd82689f5467803190e942695ebc25e2db92fd4 100644 (file)
--- a/wcfsetup/install/files/lib/system/database/editor/MySQLDatabaseEditor.class.php
+++ b/wcfsetup/install/files/lib/system/database/editor/MySQLDatabaseEditor.class.php
@@ -1,5 +1,6 @@
 <?php
 namespace wcf\system\database\editor;
+use wcf\system\database\util\PreparedStatementConditionBuilder;
 use wcf\system\Regex;
 
 /**
@@ -56,43 +57,49 @@ class MySQLDatabaseEditor extends DatabaseEditor {
         * @inheritDoc
         */
        public function getForeignKeys($tableName) {
-               $sql = "SELECT          key_column_usage.CONSTRAINT_NAME,
-                                       key_column_usage.COLUMN_NAME,
-                                       key_column_usage.REFERENCED_TABLE_NAME,
-                                       key_column_usage.REFERENCED_COLUMN_NAME,
-                                       referential_constraints.DELETE_RULE,
-                                       referential_constraints.UPDATE_RULE
-                       FROM            INFORMATION_SCHEMA.KEY_COLUMN_USAGE key_column_usage
-                       INNER JOIN      INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS referential_constraints
-                       ON              (referential_constraints.CONSTRAINT_NAME = key_column_usage.CONSTRAINT_NAME
-                                       AND referential_constraints.CONSTRAINT_SCHEMA = key_column_usage.TABLE_SCHEMA
-                                       AND referential_constraints.TABLE_NAME = key_column_usage.TABLE_NAME)
-                       WHERE           key_column_usage.TABLE_SCHEMA = ?
-                                       AND key_column_usage.TABLE_NAME = ?";
+               $sql = "SELECT  CONSTRAINT_NAME, DELETE_RULE, UPDATE_RULE
+                       FROM    INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS
+                       WHERE   CONSTRAINT_SCHEMA = ?
+                               AND TABLE_NAME = ?";
                $statement = $this->dbObj->prepareStatement($sql);
                $statement->execute([
                        $this->dbObj->getDatabaseName(),
                        $tableName
                ]);
-               $keyInformation = $statement->fetchAll(\PDO::FETCH_ASSOC);
+               $referentialConstraints = $statement->fetchAll(\PDO::FETCH_ASSOC);
                
                $validActions = ['CASCADE', 'SET NULL', 'NO ACTION'];
                
                $foreignKeys = [];
-               foreach ($keyInformation as $information) {
-                       if (!isset($foreignKeys[$information['CONSTRAINT_NAME']])) {
-                               $foreignKeys[$information['CONSTRAINT_NAME']] = [
-                                       'columns' => [$information['COLUMN_NAME']],
-                                       'referencedColumns' => [$information['REFERENCED_COLUMN_NAME']],
-                                       'referencedTable' => $information['REFERENCED_TABLE_NAME'],
-                                       'ON DELETE' => in_array($information['DELETE_RULE'], $validActions) ? $information['DELETE_RULE'] : null,
-                                       'ON UPDATE' => in_array($information['UPDATE_RULE'], $validActions) ? $information['UPDATE_RULE'] : null
-                               ];
-                       }
-                       else {
-                               $foreignKeys[$information['CONSTRAINT_NAME']]['columns'][] = $information['COLUMN_NAME'];
-                               $foreignKeys[$information['CONSTRAINT_NAME']]['referencedColumns'][] = $information['REFERENCED_COLUMN_NAME'];
-                       }
+               foreach ($referentialConstraints as $information) {
+                       $foreignKeys[$information['CONSTRAINT_NAME']] = [
+                               'columns' => [],
+                               'referencedColumns' => [],
+                               'ON DELETE' => in_array($information['DELETE_RULE'], $validActions) ? $information['DELETE_RULE'] : null,
+                               'ON UPDATE' => in_array($information['UPDATE_RULE'], $validActions) ? $information['UPDATE_RULE'] : null
+                       ];
+               }
+               
+               if (empty($foreignKeys)) {
+                       return [];
+               }
+               
+               $conditionBuilder = new PreparedStatementConditionBuilder();
+               $conditionBuilder->add('CONSTRAINT_NAME IN (?)', [array_keys($foreignKeys)]);
+               $conditionBuilder->add('TABLE_SCHEMA = ?', [$this->dbObj->getDatabaseName()]);
+               $conditionBuilder->add('TABLE_NAME = ?', [$tableName]);
+               
+               $sql = "SELECT  CONSTRAINT_NAME, COLUMN_NAME, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME
+                       FROM    INFORMATION_SCHEMA.KEY_COLUMN_USAGE
+                       " . $conditionBuilder;
+               $statement = $this->dbObj->prepareStatement($sql);
+               $statement->execute($conditionBuilder->getParameters());
+               $keyColumnUsage = $statement->fetchAll(\PDO::FETCH_ASSOC);
+               
+               foreach ($keyColumnUsage as $information) {
+                       $foreignKeys[$information['CONSTRAINT_NAME']]['columns'][] = $information['COLUMN_NAME'];
+                       $foreignKeys[$information['CONSTRAINT_NAME']]['referencedColumns'][] = $information['REFERENCED_COLUMN_NAME'];
+                       $foreignKeys[$information['CONSTRAINT_NAME']]['referencedTable'] = $information['REFERENCED_TABLE_NAME'];
                }
                
                foreach ($foreignKeys as $keyName => $keyData) {