Similar problem observed on forum thread: http://www.zabbix.com/forum/showthread.php?t=13278

I also observed this with mysql but I haven't verified since we were planning to use Oracle anyways.

21823:20091020:010158 In send_list_of_active_checks_json()
21823:20091020:010158 In get_hostid_by_host(host:'lets.hide.my.host.com')
21823:20091020:010158 Query [select hostid from hosts where host='lets.hide.my.host.com' and hostid between 000000000000000 and 099999999999999]
21890:20091020:010159 Query [select a.alertid,a.mediatypeid,a.sendto,a.subject,a.message,a.status,mt.mediatypeid,mt.type,mt.description,mt.smtp_server,mt.smtp_helo,mt.smtp_email,mt.exec_path,mt.gsm_modem,mt.username,mt.passwd,a.retries from alerts a,media_type mt where a.status=0 and a.mediatypeid=mt.mediatypeid and a.alerttype=0 and mt.mediatypeid between 000000000000000 and 099999999999999 order by a.clock]
21802:20091020:010207 In ping_database()
21900:20091020:010239 [Z3001] Connection to database 'zabbix/somecrappypasshere@ZABBIX' failed: [0] sqlo_connect
21802:20091020:010240 One child process died. Exiting ...
21805:20091020:010240 Got signal. Exiting ...
21806:20091020:010240 Got signal. Exiting ...
21807:20091020:010240 Got signal. Exiting ...
21808:20091020:010240 Got signal. Exiting ...
21809:20091020:010240 Got signal. Exiting ...
21811:20091020:010240 Got signal. Exiting ...
21812:20091020:010240 Got signal. Exiting ...
21813:20091020:010240 Got signal. Exiting ...
21814:20091020:010240 Got signal. Exiting ...
21815:20091020:010240 Got signal. Exiting ...
21816:20091020:010240 Got signal. Exiting ...
21817:20091020:010240 Got signal. Exiting ...
21820:20091020:010240 Got signal. Exiting ...
21823:20091020:010240 Got signal. Exiting ...
21850:20091020:010240 Got signal. Exiting ...
21861:20091020:010240 Got signal. Exiting ...
21865:20091020:010240 Got signal. Exiting ...
21884:20091020:010240 Got signal. Exiting ...
21885:20091020:010240 Got signal. Exiting ...
21888:20091020:010240 Got signal. Exiting ...
21901:20091020:010240 Got signal. Exiting ...
21902:20091020:010241 Got signal. Exiting ...
21905:20091020:010241 Got signal. Exiting ...
21912:20091020:010241 Got signal. Exiting ...
21913:20091020:010241 Got signal. Exiting ...
21916:20091020:010241 Got signal. Exiting ...
21919:20091020:010241 Got signal. Exiting ...
21922:20091020:010241 Got signal. Exiting ...
21923:20091020:010241 Got signal. Exiting ...
21810:20091020:010240 Got signal. Exiting ...
21864:20091020:010242 Got signal. Exiting ...
21890:20091020:010242 Got signal. Exiting ...
21897:20091020:010242 Got signal. Exiting ...
21848:20091020:010243 Got signal. Exiting ...
21867:20091020:010243 Got signal. Exiting ...
21877:20091020:010243 Got signal. Exiting ...
21828:20091020:010244 Got signal. Exiting ...
21872:20091020:010244 Got signal. Exiting ...
21802:20091020:010246 [Z3001] Connection to database 'zabbix/somecrappypasshere@ZABBIX' failed: [0] sqlo_connect