This patch was in WoA, but that was wrong I think - we got a patch on January 15, followed by a benchmark by Pavel Stehule, so I think it should still be in "needs review". So I've updated it and moved it to the next CF.
regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
