Re: enhance SPI to support EXECUTE commands

čt 5. 9. 2019 v 10:25 odesílatel Quan Zongliang <
zongliang(dot)quan(at)postgresdata(dot)com> napsal:

> On 2019/9/5 15:09, Pavel Stehule wrote:
> >
> >
> > čt 5. 9. 2019 v 8:39 odesílatel Quan Zongliang
> > <zongliang(dot)quan(at)postgresdata(dot)com
> > <mailto:zongliang(dot)quan(at)postgresdata(dot)com>> napsal:
> >
> > Dear hackers,
> >
> > I found that such a statement would get 0 in PL/pgSQL.
> >
> > PREPARE smt_del(int) AS DELETE FROM t1;
> > EXECUTE 'EXECUTE smt_del(100)';
> > GET DIAGNOSTICS j = ROW_COUNT;
> >
> > In fact, this is a problem with SPI, it does not support getting
> result
> > of the EXECUTE command. I made a little enhancement. Support for the
> > number of rows processed when executing INSERT/UPDATE/DELETE
> statements
> > dynamically.
> >
> >
> > Is there some use case for support this feature?
> >
> A user deletes the data in PL/pgSQL using the above method, hoping to do
> more processing according to the number of rows affected, and found that
> each time will get 0.
>
> Sample code:
> PREPARE smt_del(int) AS DELETE FROM t1 WHERE c=$1;
> EXECUTE 'EXECUTE smt_del(100)';
> GET DIAGNOSTICS j = ROW_COUNT;
>

This has not sense in plpgsql. Why you use PREPARE statement explicitly?

> IF j=1 THEN
> do something
> ELSIF j=0 THEN
> do something
>
> Here j is always equal to 0.
>

>
> Regards
>
> > Regards
> >
> > Pavel
> >
> >
> > Regards,
> > Quan Zongliang
> >
>
>