My Debian MySQL installation gives this:Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3306Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [Note]   - '127.0.0.1' resolves to '127.0.0.1';Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [Note] Server socket created on IP: '127.0.0.1'.Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/events_waits_current.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'events_waits_current' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/events_waits_history.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'events_waits_history' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/events_waits_history_long.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'events_waits_history_long' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/setup_consumers.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'setup_consumers' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/setup_instruments.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'setup_instruments' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/setup_timers.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'setup_timers' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/performance_timers.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'performance_timers' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/threads.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'threads' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/events_waits_summary_by_thread_by_event_name.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'events_waits_summary_by_thread_by_event_name' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/events_waits_summary_by_instance.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'events_waits_summary_by_instance' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/events_waits_summary_global_by_event_name.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'events_waits_summary_global_by_event_name' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/file_summary_by_event_name.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'file_summary_by_event_name' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/file_summary_by_instance.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'file_summary_by_instance' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/mutex_instances.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'mutex_instances' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/rwlock_instances.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'rwlock_instances' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/cond_instances.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'cond_instances' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] /usr/sbin/mysqld: Can't find file: './performance_schema/file_instances.frm' (errno: 13)Sep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [ERROR] Native table 'performance_schema'.'file_instances' has the wrong structureSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [Note] Event Scheduler: Loaded 0 eventsSep 25 13:38:09 xint01 mysqld: 140925 13:38:09 [Note] /usr/sbin/mysqld: ready for connections.:Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: Running 'mysql_fix_privilege_tables'...Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1007 (HY000) at line 160: Can't create database 'performance_schema'; database existsSep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 183: Can't create table 'cond_instances' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 213: Can't create table 'events_waits_current' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 227: Can't create table 'events_waits_history' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 241: Can't create table 'events_waits_history_long' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 262: Can't create table 'events_waits_summary_by_instance' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 283: Can't create table 'events_waits_summary_by_thread_by_event_name' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 303: Can't create table 'events_waits_summary_global_by_event_name' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 320: Can't create table 'file_instances' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 339: Can't create table 'file_summary_by_event_name' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 359: Can't create table 'file_summary_by_instance' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 376: Can't create table 'mutex_instances' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 394: Can't create table 'performance_timers' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 412: Can't create table 'rwlock_instances' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 428: Can't create table 'setup_consumers' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 445: Can't create table 'setup_instruments' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 461: Can't create table 'setup_timers' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: ERROR 1005 (HY000) at line 478: Can't create table 'threads' (errno: 13)Sep 25 13:38:10 xint01 /etc/mysql/debian-start[20151]: FATAL ERROR: Upgrade failedIt does not seem to affect MySQL, but how can I remove/fix this?mysql --versionmysql  Ver 14.14 Distrib 5.5.38, for debian-linux-gnu (x86_64) using readline 6.2-- EDIT --It seems it is related to mysql_upgrade which gives the same errors after the ':' above.
MySQL startup errors: ERROR 1005
debian;mysql
Errno 13 means permission denied, either the files themselves aren't readable and/or the directories leading to the files aren't accessible (/, /var, /var/lib need execute permissions for the mysql user, /var/lib/mysql and below needs read/write/execute).In this case it looks like it's limited to the mysql/performance_schema directory under /var/lib/mysql; fix that directory to show the same permissions, user/group as e.g. the mysql/mysql directory.EDIT: replaced spool with lib as pointed out by Ole.