MYSQLND_MAX_ALLOWED_USER_LEN 462 mysqlnd/mysqlnd_wireprotocol.c #define AUTH_WRITE_BUFFER_LEN (MYSQLND_HEADER_SIZE + MYSQLND_MAX_ALLOWED_USER_LEN + SCRAMBLE_LENGTH + MYSQLND_MAX_ALLOWED_DB_LEN + 1 + 1024) MYSQLND_MAX_ALLOWED_USER_LEN 490 mysqlnd/mysqlnd_wireprotocol.c len = MIN(strlen(packet->user), MYSQLND_MAX_ALLOWED_USER_LEN);