pt-online-schema-change¶ NAME¶ pt-online-schema-change - ALTER tables without locking them. SYNOPSIS¶ Usage¶ pt-online-schema-change alters a table’s structure without blocking reads or writes. Specify the database and table in the DSN. Do not use this tool before reading its documentation and checking your backups carefully. Add a column to sakila.actor: RISKS¶ Percona Toolkit is mature, proven i