[pgaddict]

FWIW, a simple benchmark by David Rowley (one of the authors of the patch) are here:

http://blog.2ndquadrant.com/parallel-aggregate/

[andruby]

The article claims a near linear speedup for a very large query. On a 64 core machine, the query takes:

1375s with 0 workers

131s with 10 workers

56s with 30 workers