I'm rebasing another implementation of this against current HEAD at the
moment. It was well tested but has bitrotted a bit, in particular it
needs merging with the multixact changes (eep).
That should provide a useful basis for comparison and a chance to share
ideas.
I'll follow up with the patch and a git tree when it's ready, hopefully
tonight.
-- Craig Ringer http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services