Hello Igor, This patch: commit 2cfc450bf78c2d951729d1a0e8f731c0d987b1d5 Author: Igor Babaev <igor@askmonty.org> Date: Tue Feb 9 12:35:59 2016 -0800 seems to have introduced this bug: MDEV-11081 Cursor fetches NULL for aggregate functions Can you please have a look? Thanks!