Thread: Unused function parameter in get_qual_from_partbound()

Hi,

I noticed that the first function parameter in get_qual_from_partbound(**Relation rel**, Relation parent,
is not used in the function.

Is it better to remove it like the attached patch ?

Best regards,
houzj

On Tue, 8 Jun 2021 at 21:50, houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
> I noticed that the first function parameter in get_qual_from_partbound(**Relation rel**, Relation parent,
> is not used in the function.
>
> Is it better to remove it like the attached patch ?

Going by [1] it was used when it went in. It looks like it was for
mapping attribute numbers between parent and partition rels.

Going by [2], it looks like it became unused due to the attribute
mapping code being moved down into map_partition_varattnos().

As for whether we should remove it or not, because it's an external
function that an extension might want to use, it would need to wait
until at least we branch for PG15.

Likely it's best to add the patch to the July commitfest so that we
can make a decision then.

David

[1]
https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/catalog/partition.c;h=6dab45f0edf8b1617d7239652fe36f113d30fd7a;hb=f0e44751d71
[2]
https://git.postgresql.org/gitweb/?p=postgresql.git;a=blobdiff;f=src/backend/catalog/partition.c;h=874e69d8d62e8e93164093e7352756ebfd0f69bc;hp=f54e1bdf3fb52cefed9b0d2fe7ab2a169231579d;hb=0563a3a8b5;hpb=0c2070cefa0e5d097b715c9a3b9b5499470019aa

On Tuesday, June 8, 2021 7:30 PM David Rowley <dgrowleyml@gmail.com>
> On Tue, 8 Jun 2021 at 21:50, houzj.fnst@fujitsu.com <houzj.fnst@fujitsu.com>
> wrote:
> > I noticed that the first function parameter in
> > get_qual_from_partbound(**Relation rel**, Relation parent, is not used in the
> function.
> >
> > Is it better to remove it like the attached patch ?
> 
> Going by [1] it was used when it went in. It looks like it was for mapping attribute
> numbers between parent and partition rels.
> 
> Going by [2], it looks like it became unused due to the attribute mapping code
> being moved down into map_partition_varattnos().
> 
> As for whether we should remove it or not, because it's an external function
> that an extension might want to use, it would need to wait until at least we
> branch for PG15.
> 
> Likely it's best to add the patch to the July commitfest so that we can make a
> decision then.

OK, Thanks for the explanation.
Added to CF: https://commitfest.postgresql.org/33/3159/

Best regards,
houzj

On Wed, Jun 09, 2021 at 12:28:48AM +0000, houzj.fnst@fujitsu.com wrote:
> OK, Thanks for the explanation.
> Added to CF: https://commitfest.postgresql.org/33/3159/

At first glance, this looked to me like breaking something just for
sake of breaking it, but removing the rel argument could be helpful
to simplify any external code calling it as there would be no need for
this extra Relation.  So that looks like a good idea, no need to rush
that into 14 though.
--
Michael

Hello,

Googling around, I didn't find any extensions that would break from this
change. Even if there are any, this change will simplify the relevant
callsites. It also aligns the interface nicely with get_qual_for_hash,
get_qual_for_list and get_qual_for_range.

Marking this as ready for committer. It can be committed when the branch
is cut for 15.

Regards,
Soumyadeep (VMware)

> Marking this as ready for committer. It can be committed when the branch
> is cut for 15.

I see that REL_14_STABLE is already cut. So this can go in now.