database upgrade failed from 3.2 to 3.4 failed

[Jimini]

A late reply, but perhaps the easiest way to cope with the following error:
[Z3005] query failed: [1091] Can't DROP 'dservices_1'; check that column/key exists [drop index dservices_1 on dservices]

1. mysql -u USER -p
2. use zabbix; #(or whatever your zabbix db's name ist)
3. CREATE UNIQUE INDEX `dservices_1` ON `dservices`(`dcheckid`,`ip`,`port`);

Best regards,
Jimini