On the contact summary page in CiviCRM 4.6.4 with advanced logging enabled, after doing an inline edit of address or phone, an AJAX query is triggered for a logging report URL:
/civicrm/report/instance/87?reset=1&force=1§ion=2&altered_contact_id_op=eq&altered_contact_id_value=59625&cid=59625&qfKey=blah&crmPID=2&snippet=json
Report instance 87 is a reserved instance of Contact Logging Report (Summary) with report_id logging/contact/summary .
This is a problem on a site with a large number of log entries: in this case, 4.8 million in log_civicrm_activity_contact. The logging queries take many minutes to complete. So a simple inline edit triggers heavyweight queries that slow down the database.
I'm guessing this is done in order to update the count on the Change Log tab heading. In Civi 4.4, if advanced logging is enabled then the Change Log tab heading does not show a count. This is preferable. Was the count added as a result of a feature request? Can it be disabled?