MySQL :: MySQL 8.0 Reference Manual :: 4.5.4 mysqldump — A Database Backup Program https://dev.mysql.com/doc/refman/8.0/en/mysqldump.html#mysqldump-performance
mysqldump can retrieve and dump table contents row by row, or it can retrieve the entire content from a table and buffer it in memory before dumping it. Buffering in memory can be a problem if you are dumping large tables. To dump tables row by row, use the --quick option (or --opt, which enables --quick). The --optoption (and hence --quick) is enabled by default, so to enable memory buffering, use --skip-quick.