ST_Buffer slow for large buffers, can be made faster

[pramsey]

What steps will reproduce the problem?

1. take a smallish geometry with somewhat dense vertices
2. buffer by a distance many times larger than the average inter-vertex distance
3. wait

A process that repeatedly buffers outwards, simplifying the output at each step, will return much faster than a one-step process. if your buffer distance is 1000 times your intervertex distance, try doing buffer(1), simplify(1), buffer(10), simplify(10), buffer(100), simplify(100), etc.