MySQL Cluster splits from MySQL — not pluggable?

Kaj just announced that as of 5.1.25, MySQL Cluster will no longer be included in the normal MySQL packages. Instead, a new branch is being created for MySQL Cluster releases, where the first release is informally called “6.2.15” but the releases are really named “mysql-5.1.23-ndb-6.2.15”. This new branch is based on the MySQL Cluster Carrier Grade Edition of MySQL.

Overall, this seems like a good idea — the needs for releases, schedules, pressures, etc., are at odds between MySQL Cluster and MySQL’s core. I am, however, baffled by the decision of how to release the new product: coupled with MySQL as a single monolithic package with compiled-in storage engine. After all, 5.1 has long been touted to have this amazing new pluggable storage engine architecture. Why not use it?

With Oracle/InnoDB recently announcing that they are decoupling from MySQL and releasing their storage engine as a plugin, this would make so much sense. The only thing I can think of is that MySQL and/or the MySQL Cluster team must think that the pluggable storage engine concept is not workable in its current state or easy enough to use… which I would agree1 with absolutely. However, having a team within MySQL really pushing a product and using the pluggable interface to make their releases would help dramatically to make the interface really usable for the rest of the world.

Why not do it? Let’s hear it…

1 My short-list of gripes, by no way complete: The error message interface sucks, no way to compile a plugin outside of the MySQL source (or even symlink it into the source tree), plugins are tied to an exact version of MySQL server, and no reasonable way to manage plugins in an OS context (RPMs, .debs, etc).