2015-02-10 14:32 GMT+01:00 Marc Balmer <m...@msys.ch>: > > > Am 10.02.15 um 09:06 schrieb Pavel Stehule: > > Hi > > > > > > the patch can be very simple: > > > > diff --git a/src/backend/commands/portalcmds.c > > b/src/backend/commands/portalcmds.c > > new file mode 100644 > > index 2794537..20b9206 > > *** a/src/backend/commands/portalcmds.c > > --- b/src/backend/commands/portalcmds.c > > *************** PerformPortalFetch(FetchStmt *stmt, > > *** 181,189 **** > > > > /* Return command status if wanted */ > > if (completionTag) > > ! snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s %ld", > > stmt->ismove ? "MOVE" : "FETCH", > > ! nprocessed); > > } > > > > /* > > --- 181,190 ---- > > > > /* Return command status if wanted */ > > if (completionTag) > > ! snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s %ld > > %ld", > > stmt->ismove ? "MOVE" : "FETCH", > > ! nprocessed, > > ! portal->portalPos); > > } > > > > /* > > > > That is simple indeed. I tend to think, however, that it would be > cleaner to return the position as a proper result from a functionn > instead of using a "side effect" from a FETCH/MOVE command. >
I have not strong opinion about it Pavel > > > > 2015-02-09 10:59 GMT+01:00 Marc Balmer <m...@msys.ch <mailto: > m...@msys.ch>>: > > > > > > > > 2015-02-09 10:37 GMT+01:00 Marc Balmer <m...@msys.ch > > <mailto:m...@msys.ch> <mailto:m...@msys.ch <mailto:m...@msys.ch>>>: > > > > > > Currently there are FETCH and the (non standard) MOVE commands > to work > > > on cursors. > > > > > > (I use cursors to display large datasets in a page-wise way, > where the > > > user can move per-page, or, when displaying a single record, > per record. > > > When the user goes back from per-record view to page-view, I > have to > > > restore the cursor to the position it was on before the user > changed to > > > per-record view.) > > > > > > I have to "manually" keep track of the cursor position, but in > some > > > cases it would definitely be easier to just query the current > cursor > > > position directly from the database and later use "MOVE > ABSOLUTE" to > > > rewind it to that position. That could be achieved e.g. by a > > > hypothetical "TELL <cursor-name>" command. It does, however, > not exist > > > and I have not found an alternative. Is there a way to query > the > > > current cusros position at all? If not, does a TELL command > sound like > > > a good or bad idea? > > > > > > > > > It sounds like good idea. > > > > > > Do we need a new statement? We can implement returning the > position to > > > MOVE statement. It returns a delta, but it can returns a absolute > > > position too. > > > > On second thought, a new statement is not needed at all. As Heikki > > noticed in hsi reply, it could either be a new function or have move > to > > return the current position somehow(tm). Or a nw option to move, > maybe > > "MOVE NOT" (don't move the cursor but return it's position? > > > > > > -- > > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org > > <mailto:pgsql-hackers@postgresql.org>) > > To make changes to your subscription: > > http://www.postgresql.org/mailpref/pgsql-hackers > > > > >
