On Sat, Feb 26, 2011 at 12:52:40AM -0500, Robert Haas wrote:
> On Sat, Feb 26, 2011 at 12:30 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> >> Yay! I'm excited about this, particularly the possible "pipelining"
> >> stuff, where you can do WITH (DELETE .. RETURNING ..) INSERT ... and
> >> have it be like cool and fast and stuff.
> >> Or at least I hope you can do that.
> > It's gonna need some work yet. As things stand, the tuples are indeed
> > pipelined through, but the CteScan nodes *also* stash them aside into
> > tuplestores, just in case somebody demands a rescan. Fixing that will
> > require revisiting the exec flags (EXEC_FLAG_REWIND etc). We don't
> > currently distinguish "it's unlikely you'll have to rescan" from
> > "you're guaranteed not to have to rescan", but a CteScan that's covering
> > a ModifyTable has to know the latter to not have to keep hold of copies
> > of the RETURNING tuples.
> > It might be a small enough change to do after alpha starts, but I don't
> > have time for it right now.
> Well, if nothing else, the potential is there for a future release.
That's kinda where I am on this one. In the grand PostgreSQL
tradition, we can have something that works before we have something
that works fast :)
> I'm probably not quite as excited about this feature as David Fetter
> (and my 100-Watt lightbulb is not quite as bright as the sun at high
> noon in midsummer) but I do think it's pretty cool, and I appreciate
> you getting it in, even in a somewhat basic form.
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david(dot)fetter(at)gmail(dot)com
Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate
In response to
pgsql-hackers by date
|Next:||From: Anton||Date: 2011-02-26 23:40:28|
|Subject: Native XML|
|Previous:||From: Marko Tiikkaja||Date: 2011-02-26 22:01:45|
|Subject: Re: wCTE: why not finish sub-updates at the end, not the