On 2 November 2017 at 01:55, Robert Haas <robertmh...@gmail.com> wrote: > On Wed, Nov 1, 2017 at 7:49 AM, Craig Ringer <cr...@2ndquadrant.com> wrote: >> If the client wants to fetch in chunks it can use a portal and limited >> size fetches. That shouldn't (?) be parallel-unsafe, since nothing >> else can happen in the middle anyway. > > I believe sending a limited-size fetch forces serial execution > currently. If it's true that nothing else can happen in the middle > then we could relax that, but I don't see why that should be true?
Perhaps the question is not "why" but "when"? If a parallel cursor is requested, we could simply prevent other intermediate commands other than FETCH (next). -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
