Обсуждение: Include the dependent extension information in describe command.

Hi,

Currently we do not include the dependent extension information for
index and materialized view in the describe command. I felt it would
be useful to include this information as part of the describe command
like:
\d+ idx_depends
                  Index "public.idx_depends"
 Column |  Type   | Key? | Definition | Storage | Stats target
--------+---------+------+------------+---------+--------------
 a      | integer | yes  | a          | plain   |
btree, for table "public.tbl_idx_depends"
Depends:
    "plpgsql"

Attached a patch for the same. Thoughts?

Regards,
Vignesh

vignesh C <vignesh21@gmail.com> writes:
> Currently we do not include the dependent extension information for
> index and materialized view in the describe command. I felt it would
> be useful to include this information as part of the describe command
> like:
> \d+ idx_depends
>                   Index "public.idx_depends"
>  Column |  Type   | Key? | Definition | Storage | Stats target
> --------+---------+------+------------+---------+--------------
>  a      | integer | yes  | a          | plain   |
> btree, for table "public.tbl_idx_depends"
> Depends:
>     "plpgsql"

> Attached a patch for the same. Thoughts?

This seems pretty much useless noise to me.  Can you point to
any previous requests for such a feature?  If we did do it,
why would we do it in such a narrow fashion (ie, only dependencies
of two specific kinds of objects on one other specific kind of
object)?  Why did you do it in this direction rather than
the other one, ie show dependencies when examining the extension?

            regards, tom lane

On Sun, Aug 14, 2022 at 11:07 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> vignesh C <vignesh21@gmail.com> writes:
> > Currently we do not include the dependent extension information for
> > index and materialized view in the describe command. I felt it would
> > be useful to include this information as part of the describe command
> > like:
> > \d+ idx_depends
> >                   Index "public.idx_depends"
> >  Column |  Type   | Key? | Definition | Storage | Stats target
> > --------+---------+------+------------+---------+--------------
> >  a      | integer | yes  | a          | plain   |
> > btree, for table "public.tbl_idx_depends"
> > Depends:
> >     "plpgsql"
>
> > Attached a patch for the same. Thoughts?
>
> This seems pretty much useless noise to me.  Can you point to
> any previous requests for such a feature?  If we did do it,
> why would we do it in such a narrow fashion (ie, only dependencies
> of two specific kinds of objects on one other specific kind of
> object)?  Why did you do it in this direction rather than
> the other one, ie show dependencies when examining the extension?

While implementing logical replication of "index which depends on
extension", I found that this information was not available in any of
the \d describe commands. I felt having this information in the \d
describe command will be useful in validating the "depends on
extension" easily. Now that you pointed out, I agree that it will be
better to show the dependencies from the extension instead of handling
it in multiple places. I will change it to handle it from extension
and post an updated version soon for this.

Regards,
Vignesh

On Sun, Aug 14, 2022 at 10:24 PM vignesh C <vignesh21@gmail.com> wrote:
>
> On Sun, Aug 14, 2022 at 11:07 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >
> > vignesh C <vignesh21@gmail.com> writes:
> > > Currently we do not include the dependent extension information for
> > > index and materialized view in the describe command. I felt it would
> > > be useful to include this information as part of the describe command
> > > like:
> > > \d+ idx_depends
> > >                   Index "public.idx_depends"
> > >  Column |  Type   | Key? | Definition | Storage | Stats target
> > > --------+---------+------+------------+---------+--------------
> > >  a      | integer | yes  | a          | plain   |
> > > btree, for table "public.tbl_idx_depends"
> > > Depends:
> > >     "plpgsql"
> >
> > > Attached a patch for the same. Thoughts?
> >
> > This seems pretty much useless noise to me.  Can you point to
> > any previous requests for such a feature?  If we did do it,
> > why would we do it in such a narrow fashion (ie, only dependencies
> > of two specific kinds of objects on one other specific kind of
> > object)?  Why did you do it in this direction rather than
> > the other one, ie show dependencies when examining the extension?
>
> While implementing logical replication of "index which depends on
> extension", I found that this information was not available in any of
> the \d describe commands. I felt having this information in the \d
> describe command will be useful in validating the "depends on
> extension" easily. Now that you pointed out, I agree that it will be
> better to show the dependencies from the extension instead of handling
> it in multiple places. I will change it to handle it from extension
> and post an updated version soon for this.

I have updated the patch to display "Objects depending on extension"
as describe extension footer. The changes for the same are available
in the v2 version patch attached. Thoughts?

Regards,
Vignesh

On Mon, Aug 15, 2022 at 10:09:29PM +0530, vignesh C wrote:
> I have updated the patch to display "Objects depending on extension"
> as describe extension footer. The changes for the same are available
> in the v2 version patch attached. Thoughts?

I wonder if we would be better off with a backslash command that showed
the dependencies of any object.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Indecision is a decision.  Inaction is an action.  Mark Batterson

On Tue, Aug 16, 2022 at 9:04 PM Bruce Momjian <bruce@momjian.us> wrote:
>
> On Mon, Aug 15, 2022 at 10:09:29PM +0530, vignesh C wrote:
> > I have updated the patch to display "Objects depending on extension"
> > as describe extension footer. The changes for the same are available
> > in the v2 version patch attached. Thoughts?
>
> I wonder if we would be better off with a backslash command that showed
> the dependencies of any object.

Yes, If we have a backslash command which could show the dependencies
of the specified object could be helpful.
Can we something like below:
a) Index idx1 depend on table t1
create table t1(c1 int);
create index idx1 on t1(c1);
postgres=# \dD idx1
Name
---------
idx1
Depends on:
    table t1

b) Index idx1 depend on table t1 and extension ext1
alter index idx idx1 depends on extension ext1
postgres=# \dD idx1
Name
---------
idx1
Depends on:
    table t1
    extension ext1

c) materialized view mv1 depends on table t1
create materialized view mv1 as select  * from t1;
postgres=# \dD mv1
Name
---------
mv1
Depends on:
    table t1

If you are ok with this approach, I can implement a patch on similar
lines. Thoughts?

Regards,
Vignesh