Re: Re: proposal - psql: possibility to specify sort fordescribe commands, when size is printed - Mailing list pgsql-hackers

On Fri, Mar 10, 2017 at 6:06 PM, Pavel Stehule <pavel.stehule@gmail.com> wrote:

2017-03-10 16:00 GMT+01:00 Alexander Korotkov <a.korotkov@postgrespro.ru>:

On Fri, Mar 10, 2017 at 5:16 PM, Stephen Frost <sfrost@snowman.net> wrote:

* Peter Eisentraut (peter.eisentraut@2ndquadrant.com) wrote:
> On 2/24/17 16:32, Pavel Stehule wrote:
> >     set EXTENDED_DESCRIBE_SORT size_desc
> >     \dt+
> >     \l+
> >     \di+
> >
> >     Possible variants: schema_table, table_schema, size_desc, size_asc
>
> I can see this being useful, but I think it needs to be organized a
> little better.
>
> Sort key and sort direction should be separate settings.
>
> I'm not sure why we need to have separate settings to sort by schema
> name and table name.  But if we do, then we should support that for all
> object types.  I think maybe that's something we shouldn't get into
> right now.
>
> So I would have one setting for sort key = {name|size} and on for sort
> direction = {asc|desc}.

Perhaps I'm trying to be overly cute here, but why not let the user
simply provide a bit of SQL to be put at the end of the query?

That is, something like:

\pset EXTENDED_DESCRIBE_ORDER_LIMIT 'ORDER BY 5 DESC LIMIT 10'

I think that's the question of usability.  After all, one can manually type corresponding SQL instead of \d* commands.  However, it's quite cumbersome to do this every time.

I found quite useful to being able to switch between different sortings quickly.  For instance, after seeing tables sorted by name, user can require them sorted by size descending, then sorted by size ascending, etc...

Therefore, I find user-defined SQL clause to be cumbersome.  Even psql variable itself seems to be cumbersome for me.

I would propose to add sorting as second optional argument to \d* commands.  Any thoughts?

This proposal was here already - maybe two years ago. The psql command parser doesn't allow any complex syntax - more - the more parameters in one psql commands is hard to remember, hard to read.

Could you please provide a link to this discussion.  Probably working with multiple parameters in psql commands require some rework, but that's definitely doable.

 

With my proposal, and patch I would to cover following use case. It is real case. Anytime when we used \dt+ in psql we needed sort by size desc. When we should to see a size, then the top is interesting. This case is not absolute, but very often, so I would to create some simple way, how to do some parametrization (really simple).

We could combine both approaches: add parameters to psql commands and add psql DEFAULT_(SORT_COLUMNS|DIRECTION|LIMIT) parameters.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com

The Russian Postgres Company