Further investigation showed what this change happened when mysql.init script from MySQL 5.7 was merged into build-ps/debian/percona-server-server-5.7.mysql.init
Oracle version 5.6 called mysqld_safe as mysql user while Percona's init script did not.
I am not sure if we should revert this merge at this stage, but having this somewhere in our release notes will be good.
Further investigation showed what this change happened when mysql.init script from MySQL 5.7 was merged into build-ps/ debian/ percona- server- server- 5.7.mysql. init
Oracle version 5.6 called mysqld_safe as mysql user while Percona's init script did not.
I am not sure if we should revert this merge at this stage, but having this somewhere in our release notes will be good.