Use LONGTEXT instead of the TEXT data type in MySQL to avoid size constraints...

Use LONGTEXT instead of the TEXT data type in MySQL to avoid size constraints in the latter. This resolves #399.

lib/SimpleSAML/Store/SQL.php

@@ -95,7 +95,12 @@ class SimpleSAML_Store_SQL extends SimpleSAML_Store {
 			return;
 		}
 
-		$query = 'CREATE TABLE ' . $this->prefix . '_kvstore (_type VARCHAR(30) NOT NULL, _key VARCHAR(50) NOT NULL, _value TEXT NOT NULL, _expire TIMESTAMP, PRIMARY KEY (_key, _type))';
+		$text_t = 'TEXT';
+		if ($this->driver === 'mysql') {
+			// TEXT data type has size constraints that can be hit at some point, so we use LONGTEXT instead
+			$text_t = 'LONGTEXT';
+		}
+		$query = 'CREATE TABLE ' . $this->prefix . '_kvstore (_type VARCHAR(30) NOT NULL, _key VARCHAR(50) NOT NULL, _value '.$text_t.' NOT NULL, _expire TIMESTAMP, PRIMARY KEY (_key, _type))';
 		$this->pdo->exec($query);
 
 		$query = 'CREATE INDEX ' . $this->prefix . '_kvstore_expire ON '  . $this->prefix . '_kvstore (_expire)';