VP, Chief Database Scientist @ EnterpriseDB, PostgreSQL Major Contributor and Committer Tom Lane committed a patch for index-only scans by myself and Ibrar Ahmed, which also incorporated some previous work by Heikki Linnakangas, after hacking on it some more himself. Woohoo! There is, of course, more work to be done here - performance fine-tuning, cost estimation, extensions to the core functional