#27250 limiting GET_LOCK key up to 64 char due to changes in MySQL 5.7.5 and later

Author: oleg-andreyev

Session/Storage/Handler/PdoSessionHandler.php

@@ -552,14 +552,16 @@ private function doAdvisoryLock($sessionId)
     {
         switch ($this->driver) {
             case 'mysql':
+                // MySQL 5.7.5 and later enforces a maximum length on lock names of 64 characters. Previously, no limit was enforced.
+                $lockId = \substr($sessionId, 0, 64);
                 // should we handle the return value? 0 on timeout, null on error
                 // we use a timeout of 50 seconds which is also the default for innodb_lock_wait_timeout
                 $stmt = $this->pdo->prepare('SELECT GET_LOCK(:key, 50)');
-                $stmt->bindValue(':key', $sessionId, \PDO::PARAM_STR);
+                $stmt->bindValue(':key', $lockId, \PDO::PARAM_STR);
                 $stmt->execute();
 
                 $releaseStmt = $this->pdo->prepare('DO RELEASE_LOCK(:key)');
-                $releaseStmt->bindValue(':key', $sessionId, \PDO::PARAM_STR);
+                $releaseStmt->bindValue(':key', $lockId, \PDO::PARAM_STR);
 
                 return $releaseStmt;
             case 'pgsql':