copyObject() ?

"Hiroshi Inoue" <Inoue@tpf.co.jp> writes:

AFAIC the relation between objects is not copied correctly
by copyObject() (i.e the same pointers to an object are copied
to different pointers by copyObject()).

True, but it seems irrelevant to me --- as Jan Wieck was just pointing
out, no code should ever depend on pointer-equality in parse trees or
plan trees anyway.

There is a way to maintain the list of (old,new) pairs during
copyObject() operations.

I think we'd be better off fixing any places that mistakenly assume
pointer compare is sufficient. You didn't say which version you were
testing, but we know there are a few bugs like that in the current
CVS sources because of collateral damage from the EXCEPT/INTERSECT
patch. I believe the plan is to either fix them or back out the patch
before 6.5.

regards, tom lane

"Hiroshi Inoue" <Inoue@tpf.co.jp> writes:

AFAIC the relation between objects is not copied correctly
by copyObject() (i.e the same pointers to an object are copied
to different pointers by copyObject()).

True, but it seems irrelevant to me --- as Jan Wieck was just pointing
out, no code should ever depend on pointer-equality in parse trees or
plan trees anyway.

There is a way to maintain the list of (old,new) pairs during
copyObject() operations.

I think we'd be better off fixing any places that mistakenly assume
pointer compare is sufficient. You didn't say which version you were
testing, but we know there are a few bugs like that in the current
CVS sources because of collateral damage from the EXCEPT/INTERSECT
patch. I believe the plan is to either fix them or back out the patch
before 6.5.

Yes, I removed a pointer comparison in the optimizer. It now uses
equal(). Someone needs to go over EXCEPT/INTERSECT code and identify
introduced problems or we are going to be chasing these introduced bugs
for months. Anyone volunteering?

-- 
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Hello all,

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: Wednesday, February 24, 1999 12:16 AM
To: Hiroshi Inoue
Cc: pgsql-hackers
Subject: Re: [HACKERS] copyObject() ?

"Hiroshi Inoue" <Inoue@tpf.co.jp> writes:

AFAIC the relation between objects is not copied correctly
by copyObject() (i.e the same pointers to an object are copied
to different pointers by copyObject()).

True, but it seems irrelevant to me --- as Jan Wieck was just pointing
out, no code should ever depend on pointer-equality in parse trees or
plan trees anyway.

If multiple references are not necessary,why we don't allocate diffrent
objects which have equal contents from the start ?

It seems very difficult to prevent developpers from using the following
fact implicitly.

The same pointers always point the equal contents.
^^^^^^^^

Different pointers (as copyObject() currently generates) which have
equal contents may have different contents some time.
Isn't it a significant differnce ?

There is a way to maintain the list of (old,new) pairs during
copyObject() operations.

I think we'd be better off fixing any places that mistakenly assume
pointer compare is sufficient. You didn't say which version you were
testing,

My environment is v6.4.2.
OK,I would test my cases again after the release of 6.5-BETA(v6.4.3?).

TIA

Hiroshi Inoue
Inoue@tpf.co.jp