In our testing environment, we have 100 hosts linked to a template with 1 discovery rule.

At first, each discovery rule generated 100 entities. Then, we made the discovery rule generate only 10 entities, which means that undiscoverable entities had to be removed.

This resulted in a big load on the database and the following errors showed up in the server log file:

29695:20140127:173712.267 [Z3005] query failed: [-1] ORA-00060: deadlock detected while waiting for resource [delete from sysmaps_elements where elementtype=2 and elementid between 68878 and 68972]