Extract resolvers into separate plugins to allow administrator to decide which resolvers to use.
JENKINS-15440Emailing users at the end of a failed build very slow for big Jenkins instance using subversion
JENKINS-16389Emailing users at the end of a failed build very slow for big Jenkins instance using CVS
JENKINS-16342asynchPeople very slow when using Gravatar & Subversion plugins
JENKINS-14755Mail address resolution can take a significant amount of time
is related to
JENKINS-11990After updating Active Directory plugin the Jenkins People database is experiencing massive performance issues synching because it is trying to authenticate users that are no longer in company Active Directory but are part of the Jenkins Database