Steps to reproduce:

1. After update the version Zabbix4.0 from aplpha 6 to 8, zabbix server got error while data base upgrading.
2. The result iis same in re-executing.

Result:

/var/log/zabbix/zabbix_server.log 

2670:20180622:091933.696 Got signal [signal:15(SIGTERM),sender_pid:5239,sender_uid:0,reason:0]. Exiting ...
2481:20180622:091933.766 One child process died (PID:2678,exitcode/signal:1). Exiting ...
2481:20180622:091935.767 [Z3001] connection to database 'zabbix' failed: [2002] Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.soc
2481:20180622:091935.767 Cannot connect to the database. Exiting...
14919:20180622:092235.031 Starting Zabbix Server. Zabbix 4.0.0alpha8 (revision 81985).
14919:20180622:092235.031 ****** Enabled features ******
14919:20180622:092235.031 SNMP monitoring: YES
14919:20180622:092235.031 IPMI monitoring: NO
14919:20180622:092235.031 Web monitoring: YES
14919:20180622:092235.031 VMware monitoring: YES
14919:20180622:092235.031 SMTP authentication: NO
14919:20180622:092235.031 Jabber notifications: NO
14919:20180622:092235.031 Ez Texting notifications: YES
14919:20180622:092235.031 ODBC: NO
14919:20180622:092235.031 SSH2 support: NO
14919:20180622:092235.031 IPv6 support: YES
14919:20180622:092235.031 TLS support: NO
14919:20180622:092235.031 ******************************
14919:20180622:092235.031 using configuration file: /usr/local/etc/zabbix_server.conf
14919:20180622:092236.157 current database version (mandatory/optional): 03050068/03050068
14919:20180622:092236.157 required mandatory version: 03050120
14919:20180622:092236.157 starting automatic database upgrade
14919:20180622:092237.133 completed 1% of database upgrade
14919:20180622:092237.134 completed 3% of database upgrade
14919:20180622:092237.135 completed 5% of database upgrade
14919:20180622:092237.136 completed 7% of database upgrade
14919:20180622:092237.151 completed 9% of database upgrade
14919:20180622:092237.257 completed 11% of database upgrade
14919:20180622:092237.260 completed 13% of database upgrade
14919:20180622:092237.262 completed 15% of database upgrade
14919:20180622:092237.264 completed 17% of database upgrade
14919:20180622:092237.323 completed 19% of database upgrade
14919:20180622:092237.325 completed 21% of database upgrade
14919:20180622:092237.326 completed 23% of database upgrade
14919:20180622:092237.328 completed 25% of database upgrade
14919:20180622:092237.888 completed 26% of database upgrade
14919:20180622:092238.865 completed 28% of database upgrade
14919:20180622:092238.867 completed 30% of database upgrade
14919:20180622:092238.868 completed 32% of database upgrade
14919:20180622:092238.869 completed 34% of database upgrade
14919:20180622:092238.933 completed 36% of database upgrade
14919:20180622:092238.935 completed 38% of database upgrade
14919:20180622:092238.936 completed 40% of database upgrade
14919:20180622:092238.937 completed 42% of database upgrade
14919:20180622:092238.939 completed 44% of database upgrade
14919:20180622:092238.940 completed 46% of database upgrade
14919:20180622:092238.942 completed 48% of database upgrade
14919:20180622:092238.943 completed 50% of database upgrade
14919:20180622:092238.943 completed 51% of database upgrade
14919:20180622:092238.944 completed 53% of database upgrade
14919:20180622:092238.945 completed 55% of database upgrade
14919:20180622:092241.817 completed 57% of database upgrade
14919:20180622:092241.819 completed 59% of database upgrade
14919:20180622:092241.830 completed 61% of database upgrade
14919:20180622:092241.832 completed 63% of database upgrade
14919:20180622:092242.320 completed 65% of database upgrade
14919:20180622:092242.454 completed 67% of database upgrade
14919:20180622:092242.559 completed 69% of database upgrade
14919:20180622:092242.629 completed 71% of database upgrade
14919:20180622:092243.906 completed 73% of database upgrade
14919:20180622:092243.957 completed 75% of database upgrade
14919:20180622:092244.134 completed 76% of database upgrade
14919:20180622:092244.483 completed 78% of database upgrade
14919:20180622:092244.487 completed 80% of database upgrade
14919:20180622:093005.039 [Z3005] query failed: [1114] The table '#sql-3a1e_3' is full [alter table `events` add `severity` integer default '0' not null]
14919:20180622:093005.039 slow query: 440.552425 sec, "alter table `events` add `severity` integer default '0' not null"
14919:20180622:093005.040 database upgrade failed
15070:20180622:093226.256 Starting Zabbix Server. Zabbix 4.0.0alpha8 (revision 81985).
15070:20180622:093226.256 ****** Enabled features ******
15070:20180622:093226.256 SNMP monitoring: YES
15070:20180622:093226.256 IPMI monitoring: NO
15070:20180622:093226.256 Web monitoring: YES
15070:20180622:093226.256 VMware monitoring: YES
15070:20180622:093226.256 SMTP authentication: NO
15070:20180622:093226.256 Jabber notifications: NO
15070:20180622:093226.256 Ez Texting notifications: YES
15070:20180622:093226.256 ODBC: NO
15070:20180622:093226.256 SSH2 support: NO
15070:20180622:093226.256 IPv6 support: YES
15070:20180622:093226.256 TLS support: NO
15070:20180622:093226.256 ******************************
15070:20180622:093226.256 using configuration file: /usr/local/etc/zabbix_server.conf
15070:20180622:093226.259 current database version (mandatory/optional): 03050110/03050110
15070:20180622:093226.259 required mandatory version: 03050120
15070:20180622:093226.259 starting automatic database upgrade
15070:20180622:093923.828 [Z3005] query failed: [1114] The table '#sql-3a1e_5' is full [alter table `events` add `severity` integer default '0' not null]
15070:20180622:093923.828 slow query: 417.568856 sec, "alter table `events` add `severity` integer default '0' not null"
15070:20180622:093923.828 database upgrade failed