These pages are treated as nullipotent, so DBPerformance log expectation are based on that. However, CentralAuth still uses the master on all POST requests (as a transitional measure). It should really only use it on requests which might write data (most particularly the CentralAuth endpoints the update user data).
Related Gerrit Patches:
|mediawiki/extensions/CentralAuth : master||Avoid using the master DB for non-write POST requests|
|mediawiki/core : master||Add WebRequest methods for determining "safe" requests|
|Open||aaron||T88445 MediaWiki active/active datacenter investigation and work (tracking)|
|Open||None||T92357 Fix problematic database master queries performed on HTTP GET/HEAD|
|Resolved||aaron||T134608 CentralAuth uses master on POST requests for API/specialpages that return false for doesWrites()|