On 2023-05-22 Mo 05:24, Pavel Stehule wrote:
po 22. 5. 2023 v 7:19 odesílatel Kirk Wolak <wol...@gmail.com> napsal:
On Fri, May 19, 2023 at 1:08 PM Andrew Dunstan
<and...@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/>
<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