Mercenaries...
We have masters and slaves but what about mercenaries? Mercenaries can serve multiple masters at the same time, each master simply carves out a small amount of the mercenary's time. Mercenaries don't have undying loyalty to one master. If a master goes away for a while a mercenary can still remain productive by doing work for other masters. In-fact if a mercenary knows that a master will be gone for a long time, they can free some resources for other masters. Mercenaries travel the world, calling in air-strikes, looking for the ace of... wait the metaphor broke.
MySQL has some great performance characteristics in multiple performance disciplines (both transaction and price) but as one who scales MySQL will attest to, there are some complicated problems to overcome as things get bigger. This is especially true of write-intensive apps. Mercenaries are servers that are not of the "slave" class who can serve multiple masters without "hating one" as the old proverb goes. Using this paradigm it's possible to divide up your write responsibilites to multiple servers and replicate those changes into your read-only cloud. Segmented tables to a given processor/machine would allow write-responsibility to be segmented to a resource-dedicated system.
Yes I know breaking up the data-structure hampers referential integrity (for those pure-dba types) but MyISAM continues to be a popular choice despite its lack of the aforementioned feature due to its performance. There is apparantly a trade-off here that some people are willing to make. Perhaps an architecture whereby certain tables are replicated as read-only to the other write masters to maintain referential integrity is the way to go? I don't think that's a drop in the hat as inserts can become complicated with referential integrity enforced due to replication lag.
I'm not so much proposing an architecture as lamenting a lacking feature. I suppose in all my free time, I could work on this but that would compete with all the time I spend writing
fibonacci numbers out on my whiteboard. FYI, MySQL 5.2 or later is supposed to include this feature but it's not here yet and as far as I know not committed to a particular release.
