I've had to take software out of production and replace it with non-infringing software.
What evidence do you have that we're in a mess?
EOLAS v Microsoft, Amazon v Barnes&Noble, Sun v NetApp..
If you don't mind my asking, where were you working when you had to replace this software?
As far as my own situation, the details are here: http://news.zdnet.co.uk/software/0,1000000121,39194883,00.ht...
Ironically it was another "ARC" patent: http://en.wikipedia.org/wiki/Adaptive_Replacement_Cache
From the article, it doesn't sound like you were required by an injunction to remove any code. Someone just read in the news about some newly issued patent and panicked. What's the plan for dealing with the 1000 other patents PostgreSQL is violating?
The PostgreSQL project tries to stick with things for which there is plenty of prior art and thankfully most of the best stuff in databases is old enough so that patents aren't a big issue.
Unfortunately some of the things people do with PostgreSQL's extensibility aren't as old. I'm sure there are some people out there using custom UDF/UDA functions that may infringe on patents.