Help:Duplicate entities

Duplicate entities should not happen but any unforeseen process termination may accidental collide with a rollback transaction and leaves an update process hanging and can therefore cause an ID request to be unsuccessful and hereby creates an new ID for an already existing entity.

Semantic MediaWiki's update transactions are atomic and should prevent those scenarios but on some rare occasions above events can still unfold and to minimize a potential impact on queries or data consistency different features CiteRef::gh:smw:2882CiteRef::gh:smw:2883 are provided.

How to resolve a duplicate entry?

 * A simple save (or purge) action should be enough for the system to detect and mark CiteRef::gh:smw:2882 duplicate entries.
 * provides a tool CiteRef::gh:smw:2883 to monitor the entity table on possible duplicate entries (it can take a moment before data are fetched and returned from a request). To avoid any excessive use of the tool, retrieved data are cached  and may not reflect the most recent status especially when listed entities have been recently (within the cacheTTL) processed.
 * allows to dispose of duplicate entities via command line. Thus is is easier to automatize this task i.e. triggering it via a cronjob.