I am not sure if this kind of issue fits bug tracker.

I am upgrading mysql database from zabbix 1.8.10 to 1.9.9 with script patch.sql. My mysql database is size about 50GB.

During an upgrade I get error:
ERROR 1452 (23000) at line 886: Cannot add or update a child row: a foreign key constraint fails (`zabbix`.<result 2 when explaining filename '#sql-2621_6'>, CONSTRAINT `c_hosts_2` FOREIGN KEY (`maintenanceid`) REFERENCES `maintenances` (`maintenanceid`))

My second try:
ERROR 1452 (23000) at line 886: Cannot add or update a child row: a foreign key constraint fails (`zabbix`.<result 2 when explaining filename '#sql-396b_2'>, CONSTRAINT `c_hosts_2` FOREIGN KEY (`maintenanceid`) REFERENCES `maintenances` (`maintenanceid`))

Temporary directory for mysql is about 65G free.

Any sugestion how can I workaround this issue and convert all database?