Re: Adding SHOW CREATE TABLE

po 22. 5. 2023 v 7:19 odesílatel Kirk Wolak <wolakk@gmail.com> napsal:

On Fri, May 19, 2023 at 1:08 PM Andrew Dunstan <andrew@dunslane.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/> and <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