Re: ltree docs imprecise about sorting order

On Wednesday, October 16, 2024, Bruce Momjian <bruce(at)momjian(dot)us> wrote:

> On Thu, May 23, 2024 at 04:17:50PM +0000, PG Doc comments form wrote:
> > The following documentation comment has been logged on the website:
> >
> > Page: https://www.postgresql.org/docs/16/ltree.html
> > Description:
> >
> > The ltree docs available at
> > https://www.postgresql.org/docs/current/ltree.html state "Comparison
> sorts
> > in the order of a tree traversal" without specifying the strategy
> > implemented to walk the tree.
> > A quick experiment suggests that the implemented solution is pre-ordered
> > depth-first search.
> > I suggest the ltree docs be amended to "Comparison sorts in the order of
> a
> > pre-ordered depth-first tree traversal".
>
> [ moved to hackers ]
>
> Can someone confirm this and/or create a patch?
>

If we are going to update the description of sorting we should probably
take the chance to mention collation, or I believe the lack thereof.
Including an example with order by wouldn’t hurt either.

The example data is also a perfect tree, all intermediate nodes exist as
their own rows. It may be informative to include exceptions to this rule.

David J.