On 30 March 2018 at 15:05, Andres Freund <and...@anarazel.de> wrote: >> + * To allow join removal to happen, we can't reference the CTID column >> + * of an otherwise-removable relation. > > A brief hint why wouldn't hurt.
Maybe something like: /* * Join removal is only ever possible when no columns of the to-be-removed relation * are referenced. If we added the CTID here then we could inadvertently disable join * removal. We'll need to delay adding the CTID until after join removal takes place. */ (I've not read the code, just the thread) -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services