On Thu, 29 Nov 2018 at 08:17, Steve Crawford <scrawf...@pinpointresearch.com> wrote: > Both for my edification and as a potentially important documentation detail, > do operations that rebuild the table such as CLUSTER or pg_repack reclaim the > column space?
I've never used pg_repack, but CLUSTER will reform the tuples so that they no longer store the actual value for the Datums belonging to the dropped column. They'll still contain the null bitmap to mention that the dropped column's value is NULL. The row won't disappear from pg_attribute, so the attnums are not resequenced, therefore we must maintain the dropped column with the NULL marking. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
