The tool management interface (mod/lti/toolconfigure.php) makes an AJAX request (mod_lti_get_tool_types) to load all the available tools.

Sites can have an unlimited number of tools configured - meaning as time goes on this request gets slower and slower.

The external webservice responsible loads all the tools in one query - and then has each one run through serialise_tool_type() - this function ends up doing a DB lookup for each tool.

Ideally, this information would be loaded in a single query rather than N queries - or the interface implements some form of paging (displaying hundreds or thousands of tools on the one page isn't ideal either after all).