Обсуждение: pgsql: Fix planning of SubLinks to ensure that Vars generated from

Log Message:
-----------
Fix planning of SubLinks to ensure that Vars generated from transformation of
a sublink's test expression have the correct vartypmod, rather than defaulting
to -1.  There's at least one place where this is important because we're
expecting these Vars to be exactly equal() to those appearing in the subplan
itself.  This is a pretty klugy solution --- it would likely be cleaner to
change Param nodes to include a typmod field --- but we can't do that in the
already-released 8.2 branch.
Per bug report from Hubert Fongarnand.

Modified Files:
--------------
    pgsql/src/backend/optimizer/plan:
        subselect.c (r1.112 -> r1.113)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/subselect.c.diff?r1=1.112&r2=1.113)

Tom Lane wrote:
> Log Message:
> -----------
> Fix planning of SubLinks to ensure that Vars generated from transformation
> of
> a sublink's test expression have the correct vartypmod, rather than
> defaulting
> to -1.  There's at least one place where this is important because we're
> expecting these Vars to be exactly equal() to those appearing in the
> subplan
> itself.  This is a pretty klugy solution --- it would likely be cleaner to
> change Param nodes to include a typmod field --- but we can't do that in
> the
> already-released 8.2 branch.
> Per bug report from Hubert Fongarnand.
>


I'm slightly confused by this commit message. Is this commit on HEAD a
temporary measure pending a cleaner fix, or is it the intended permanent
fix, notwithstanding the kludginess?

cheers

andrew

"Andrew Dunstan" <andrew@dunslane.net> writes:
> Tom Lane wrote:
>> This is a pretty klugy solution --- it would likely be cleaner to
>> change Param nodes to include a typmod field --- but we can't do that in
>> the already-released 8.2 branch.

> I'm slightly confused by this commit message. Is this commit on HEAD a
> temporary measure pending a cleaner fix, or is it the intended permanent
> fix, notwithstanding the kludginess?

I have a to-do item to look at the idea of adding typmod to Param, but
am not committing to do it yet.  In the meantime I figured the bug should
get fixed.

            regards, tom lane