Another is a recent one just committed by Alexander Korotkov which I just recently found out about on New node splitting algorithm for GIST and admit I don't know enough about to judge. I have to admit to being very clueless when it comes to the innards of index implementations so don't ask me any technical details. It's one of those short-comings among the trillion others I have that I have learned to accept will probably never change.
What it provides specifically for PostGIS is summarized in Paul's call for action noted below. As a passionate user of PostGIS
,ltree, tsearch, and hstore, I'm pretty excited about these patches and other GIST and general index enhancements and there potential use in GIST dependent extensions. I'm hoping to see
these spring to life in PostgreSQL 9.2 and think it will help to further push the envelope of where PostgreSQL can go as a defacto platform
for cutting-edge technology and scientific research. I think one of PostgreSQL's greatest strength is its extensible index API.
Thanks to the sponsorship of Michigan Technological University, we now
have 50% of the work complete. There is a working patch at the
which provides quad-tree and kd-tree indexes.
However, there is a problem: unless the patch is reviewed and goes
through more QA/QC, it'll never get into PostgreSQL proper. In case
you think I am kidding: we had a patch for KNN searching ready for the
9.0 release, but it wasn't reviewed in time, so we had to wait all the
way through the 9.1 cycle to get it.
I am looking for sponsors in the $5K to $10K range to complete this
work. If you use PostgreSQL in your business, this is a chance to add
a basic capability that may help you in all kinds of ways you don't
expect. We're talking about faster geospatial indexes here, but this
facility will also radically speed any partitioned space. (For
example, the suffix-tree, which can search through URLs incredibly
fast. Another example, you can use a suffix tree to very efficiently
index geohash strings. Interesting.)
If you think there's a possibility, please contact me and I will send
you a prospectus you can take to your manager. Let's make this happen