See also http://www.zabbix.com/forum/showthread.php?p=56849

When viewing the dashboard, the web UI frequently becomes unresponsive. Checking the process list in the database reveals a large number of threads hung up on this query:

UPDATE ids SET nextid=nextid+1 WHERE nodeid=1 AND table_name='profiles' AND field_name='profileid'

Chasing the function calls in the code, I see this:

1. get_dbid() in include/db.inc.php has the offending query on line 749.

2. the only files calling get_dbid() for updating profileid are:

insert_profile() from include/profiles.inc.php
update_node_profile() from include/nodes.inc.php

3. I doubt the dashboard is inserting profiles, so I'm guessing that update_node_profile() is probably causing the problem.

4. update_node_profile() is only used in init_nodes() from include/nodes.inc.php

5. init_nodes() is used by:

include/page_header.php
get_current_nodeid() from include/nodes.inc.php

6. page_header and get_current_nodeid() are used pretty much everywhere.

My gut feeling is that the AJAX on the dashboard is generating too many get_dbid() queries too fast, and the DB can't cope.

This has made the webui basically unusable.