We observed that when the host.delete method failed, some configuration settings on certain hosts were unintentionally removed.

The following issue occurs:

1. The host.delete method is executed in parallel via the Zabbix API.
2. Some hosts fail to be deleted.
3. For the hosts that failed to delete, part of their configuration is missing.
   A deadlock occurs during processing, causing the transaction to be interrupted and rolled back.
   Please check the following:
   After executing host.delete, there is no change in configuration for Zabbix server03, 05, and 08 compared to the state before execution.
   However, Zabbix server01, 06, and 09 have some configurations missing.
   Before execution

   +--------+----------------------+------------+---------------+-------------+----------------------+----------------------+
   | hostid | hostname             | item_count | trigger_count | graph_count | discovery_rule_count | item_prototype_count |
   +--------+----------------------+------------+---------------+-------------+----------------------+----------------------+
   |  10047 | Zabbix server health |         72 |            52 |           0 |                    3 |                   24 |
   |  10084 | Zabbix server        |        156 |            86 |          17 |                    6 |                   49 |
   |  10637 | Zabbix server01      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10638 | Zabbix server02      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10639 | Zabbix server03      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10640 | Zabbix server04      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10641 | Zabbix server05      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10642 | Zabbix server06      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10643 | Zabbix server07      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10644 | Zabbix server08      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10645 | Zabbix server09      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10646 | Zabbix server10      |       1515 |          1467 |        1408 |                    7 |                   50 |
   +--------+----------------------+------------+---------------+-------------+----------------------+----------------------+
   12 rows in set (27.96 sec)
   
   mysql>
   

   After execution

   +--------+----------------------+------------+---------------+-------------+----------------------+----------------------+
   | hostid | hostname             | item_count | trigger_count | graph_count | discovery_rule_count | item_prototype_count |
   +--------+----------------------+------------+---------------+-------------+----------------------+----------------------+
   |  10047 | Zabbix server health |         72 |            52 |           0 |                    3 |                   24 |
   |  10084 | Zabbix server        |        156 |            86 |          17 |                    6 |                   49 |
   |  10637 | Zabbix server01      |       1515 |          1467 |           0 |                    3 |                   19 |
   |  10639 | Zabbix server03      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10641 | Zabbix server05      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10642 | Zabbix server06      |       1515 |          1467 |           0 |                    3 |                   19 |
   |  10644 | Zabbix server08      |       1515 |          1467 |        1408 |                    7 |                   50 |
   |  10645 | Zabbix server09      |          0 |             0 |           0 |                    3 |                   19 |
   +--------+----------------------+------------+---------------+-------------+----------------------+----------------------+
   8 rows in set (13.93 sec)
   
   mysql>
   

I have confirmed that the issue also reproduces on version 7.0.12.