Re: Adding SHOW CREATE TABLE

On 2023-05-22 Mo 05:24, Pavel Stehule wrote:
>
>
> po 22. 5. 2023 v 7:19 odesílatel Kirk Wolak <wolakk(at)gmail(dot)com> napsal:
>
> On Fri, May 19, 2023 at 1:08 PM Andrew Dunstan
> <andrew(at)dunslane(dot)net> wrote:
>
> I think the ONLY place we should have this is in server side
> functions. More than ten years ago I did some work in this
> area (see below), but it's one of those things that have been
> on my ever growing personal TODO list
>
> See <https://bitbucket.org/adunstan/retailddl/src/master/>
> <https://bitbucket.org/adunstan/retailddl/src/master/> and
> <https://www.youtube.com/watch?v=fBarFKOL3SI>
> <https://www.youtube.com/watch?v=fBarFKOL3SI>
>
> Andrew,
>   Thanks for sharing that.  I reviewed your code. 10yrs, clearly
> it's not working (as-is, but close), something interesting about the
> structure you ended up in.  You check the type of the object and
> redirect accordingly at the top level. Hmmm...
> What I liked was that each type gets handled (I was focused on
> "table"), but I realized similarities.
>
>   I don't know what the group would think, but I like the thought
> of calling this, and having it "Correct" to call the appropriate
> function.
> But not sure it will stand.  It does make obvious that some of
> these should be spun out as "pg_get_typedef"..
> pg_get_typedef
> pg_get_domaindef
> pg_get_sequencedef
>
>   Finally, since you started this a while back, part of me is
> "leaning" towards a function:
> pg_get_columndef
>
>   Which returns a properly formatted column for a table, type, or
> domain? (one of the reasons for this, is that this is
> the function with the highest probability to change, and
> potentially the easiest to share reusability).
>
>   Finally, I am curious about your opinion.  I noticed you used
> the internal pg_ tables, versus the information_schema...
> I am *thinking* that the information_schema will be more stable
> over time... Thoughts?
>
>
> I think inside the core, the information schema is never used.  And
> there was a performance issue (fixed in PostgreSQL 12), that blocked
> index usage.
>
>

A performant server side set of functions would be written in C and
follow the patterns in ruleutils.c.

cheers

andrew

--
Andrew Dunstan
EDB:https://www.enterprisedb.com