It seems that the task of fetching next n results without moving the cursor seems like too complicated to implement for any query that has even a little bit of complication in it...
--- On Wed, 12/21/11, Robert Haas <robertmh...@gmail.com> wrote: > From: Robert Haas <robertmh...@gmail.com> > Subject: Re: [HACKERS] Cursor behavior > To: "amit sehas" <cu...@yahoo.com> > Cc: pgsql-hackers@postgresql.org > Date: Wednesday, December 21, 2011, 8:43 AM > On Thu, Dec 15, 2011 at 4:15 PM, amit > sehas <cu...@yahoo.com> > wrote: > > I had a question about the cursor internals > implementation. When you Fetch next 'n' results without > moving the cursors, is this kind of functionality > implemented by firstly executing the whole query and then > moving the cursor over the results, or are the movements > done on active database lookups, moving forward and > backward... > > I think it depends on the query. For example, I > believe that a query > involving writeable CTEs will be run to completion before > returning > any results, but I believe that a seqscan will not. > > -- > Robert Haas > EnterpriseDB: http://www.enterprisedb.com > The Enterprise PostgreSQL Company > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
