 says: "An option can be specified by writing it in full or as any unambiguous prefix. For example, the --compress option can be given to mysqldump as --compr, but not as --comp because the latter is ambiguous. Be aware that the use of option prefixes can cause problems in the event that new options are implemented for a program. A prefix that is unambiguous now might become ambiguous in the future. " This behavior is confusing and non-future proof in its basic form. Adding extra options through plugins causes option prefixes in scripts to be unreliable even across server restarts. It also "pollutes" the server options namespace and leaves very little "available" options to new plugins. This worklog aims to deprecate unique prefixes and only accept full option names. Update: Original implementation deprecated this feature in 5.7 (added warnings). Revised implementation deprecated this feature in 5.5, 5.6 (added warnings) and removed the feature in 5.7. User Documentation ================== (deprecation) (removal)