Re: [HACKERS] New partitioning - some feedback - Mailing list pgsql-hackers

On Mon, Jul 10, 2017 at 04:15:28PM +0900, Amit Langote wrote:
> On 2017/07/10 15:32, Craig Ringer wrote:
> > On 8 July 2017 at 00:03, David Fetter <david@fetter.org> wrote:
> > 
> >> On Fri, Jul 07, 2017 at 10:29:26AM +0900, Amit Langote wrote:
> >>> Hi Mark,
> >>>
> >>> On 2017/07/07 9:02, Mark Kirkwood wrote:
> >>>> I've been trying out the new partitioning in version 10. Firstly, I
> >> must
> >>>> say this is excellent - so much nicer than the old inheritance based
> >> method!
> >>>
> >>> Thanks. :)
> >>>
> >>>> My only niggle is the display of partitioned tables via \d etc. e.g:
> >>>>
> >>>> part=# \d
> >>>>                 List of relations
> >>>>  Schema |         Name         | Type  |  Owner
> >>>> --------+----------------------+-------+----------
> >>>>  public | date_fact            | table | postgres
> >>>>  public | date_fact_201705     | table | postgres
> >>>>  public | date_fact_201706     | table | postgres
> >>>>  public | date_fact_20170601   | table | postgres
> >>>>  public | date_fact_2017060100 | table | postgres
> >>>>  public | date_fact_201707     | table | postgres
> >>>>  public | date_fact_rest       | table | postgres
> >>>> (7 rows)
> >>
> >> Would showing relispartition=tru tables only in \d+ fix this?
> >> <http://www.postgresql.org/mailpref/pgsql-hackers>
> >>
> > 
> > I think so.
> 
> I posted a patch upthread which makes \d hide partitions (relispartition =
> true relations) and include them if the newly proposed '!' modifier is
> specified.  The '+' modifier is being used to show additional detail of
> relations chosen to be listed at all, so it seemed like a bad idea to
> extend its meaning to also dictate whether partitions are to be listed.
> We have a separate 'S' modifier to ask to list system objects (which are,
> by default hidden), so it made sense to me to add yet another modifier
> (aforementioned '!') for partitions.

We have already made '+' signal "more detail, unspecified," for a lot
of different cases.  If partitions are just "more detail" about a
table, which is the direction we've decided to go, it makes sense to
list them under the rubric of '+' rather than inventing yet another
hunk of syntax to psql's already confusing \ commands.

> > I'd like to add a flag of some kind to \d column output that marks a table
> > as having partitions, but I can't think of anything narrow enough and still
> > useful.
> 
> Actually, if \d had shown RELKIND_PARTITIONED_TABLE tables as of Type
> "partitioned table", we wouldn't need a separate flag for marking a table
> as having partitions.  But we've avoided using that term ("partitioned
> table") in the error messages and such, so wouldn't perhaps be a good idea
> to do that here.  But I wonder if we (also) want to distinguish
> partitioned tables from regular tables?  I understood that there is some
> desire for partitions be distinguished when they are listed in the output,
> either by default or by using a modifier.

+1 for showing that they're a different beast.

Best,
David.
-- 
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
Skype: davidfetter      XMPP: david(dot)fetter(at)gmail(dot)com

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