Обсуждение: AW: [HACKERS] Another nasty cache problem

> Chris Bitmead <chrisb@nimrod.itg.telstra.com.au> writes:
> > What about portals? Doesn't psql use portals?
> 
> No ... portals are a backend concept ...
> 

I think the previous frontend "monitor" did use a portal for the
selects. The so called "blank portal".

I don't really see any advantage, that psql does not do a fetch loop
with a portal. 
Is it possible in psql do do any "fetch" stuff, after doing a
select * from table ?

The result is fed to a pager anyway.

Andreas

Zeugswetter Andreas SB wrote:
> 
> > Chris Bitmead <chrisb@nimrod.itg.telstra.com.au> writes:
> > > What about portals? Doesn't psql use portals?
> >
> > No ... portals are a backend concept ...
> >
> 
> I think the previous frontend "monitor" did use a portal for the
> selects. The so called "blank portal".
> 
> I don't really see any advantage, that psql does not do a fetch loop
> with a portal.
> Is it possible in psql do do any "fetch" stuff, after doing a
> select * from table ?

Yes it is if you set up a cursor. I think Tom was right that psql
shouldn't use a portal just as a matter of course, because things
work differently in that case (locks?). I'm sure it could be a 
useful option though.

> 
> The result is fed to a pager anyway.
> 
> Andreas

Zeugswetter Andreas SB wrote:
> 
> > Chris Bitmead <chrisb@nimrod.itg.telstra.com.au> writes:
> > > What about portals? Doesn't psql use portals?
> >
> > No ... portals are a backend concept ...
> >
> 
> I think the previous frontend "monitor" did use a portal for the
> selects. The so called "blank portal".

Is'nt the "blank portal" the name of the cursor you get when you just 
do a select without creating a cursor ?

> I don't really see any advantage, that psql does not do a fetch loop
> with a portal.

It only increases traffic, as explicit fetch commands need to be sent 
to backend. If one does not declare a cursor, an implicit fetch all from 
blank is performed.

> Is it possible in psql do do any "fetch" stuff, after doing a
> select * from table ?

only if in a declared cursor, and you can only declare cursor if in a 
transaction.

---------------
Hannu