It's been a month since my last entry, so clearly I'm not a good blogger. Anyway:
I submitted the MultiXactId patch some time ago. Tom reviewed and committed it. We don't have the foreign key problem anymore! I was kinda ashamed by that problem, so I'm happy it's now solved. Fortunately, we figured a way to make the mechanism be used only when it's really needed, that is, only when a row is locked by two or more transactions at the same time. This way we don't even incur in a performance hit — the only point where the mechanism enters the picture is when previous Postgres' versions would block, so it's a net win.
Right now I'm looking at Heikki Linnakangas' two-phase commit patch. With some luck I can help clean it up some before it gets to Tom, so that when he gets it, we can quickly have a fully functional 2PC implementation in time for 8.1.
Additionally, I'm looking at completing my shared dependencies patch before 8.1 freezes. I let it rot some; I partly blame Stephen Frost's SQL role support patch. Of course it's a lame excuse — it'd be cool to have both things in. But they conflict anyway so I'm leaving this behind a little.