On 29/11/2018 00:04, David Rowley wrote: > 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.
committed -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
