It’s a feature preview with many limitations, but this is still good news. This has been a pretty severe performance limitation for replication in MySQL, which has prompted many a workaround.
Interestingly, the feature preview is based on MySQL 5.1, which has recently seemed to be getting some significant changes even though it’s a GA release. Does this signal a change to MySQL’s release cycle, which has sometimes been characterized as too long? More good news?