Sites with provided users generate 2 queries to SAKAI_USER_ID_MAP for every provided users whenever a permissions change is made in a tool (i.e. the authzgroup is updated).
For example a site with 100 users will generate 200 queries, of this form:
select EID from SAKAI_USER_ID_MAP where USER_ID=x'63376466303137302D663632332D346233662D303032612D303732313036373338666262'
select USER_ID from SAKAI_USER_ID_MAP where EID=x'73747564656E74313334'
These queries are not generated for non-provided users.
This is a serious scaleability issue for sites with large numbers of provided users, e.g. a site with 22K users will generate 44K queries every time a tool permissions change is made.