RDBStore is shelfed as a reference for now. The idea was to partition sql table across multiple DB servers using a consistent hash of some column. There no longer would be the convenience of autoincrement columns so UIDs are a way to make unique ids without a central table or counter.
In some cases, like when the primary key is the uid column, duplicate detection can be enforce by the DB since duplicate values would map to the same partition table and that table would have a unique index, causing a duplicate key error. This could allow for slightly smaller uids to be used with the comfort of knowing that in the unlikely event of a rare collision, it will be detected. This is why it had several uid functions. It might be nice to add a standard UUID1 and UUID4 function, though they were not useful for RDB store for B-TREE reasons. -- View this message in context: http://wikimedia.7.n6.nabble.com/Really-Fast-Merges-tp4990838p4990931.html Sent from the Wikipedia Developers mailing list archive at Nabble.com. _______________________________________________ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
