Reported by hamid sfandiari:

i installed a new 1.8.6rc.2 (revision 20861) in my lab and it hasn't any host , only it has 3 discovery rules with related action for adding discovered hosts into a group.
zabbix performance is to low and i see error like the following :

2080:20110804:092336.810 [Z3005] query failed: [1213] Deadlock found when trying to get lock; try restarting transaction [delete from escalations where escalationid=245]
2080:20110804:092406.807 [Z3005] query failed: [1213] Deadlock found when trying to get lock; try restarting transaction [delete from escalations where escalationid=258 and status=4]
2080:20110804:092502.809 [Z3005] query failed: [1213] Deadlock found when trying to get lock; try restarting transaction [delete from escalations where escalationid=282]

slow query log::
delete from escalations where actionid=4 and triggerid=0 and status not in (1,4,5) and (esc_step<>0 or status<>0);

with StartDiscoverers=10 in the config file

the problem doesn't appear when i use StartDiscoverers=1