Horton

Re: SQL-standard function body

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-04-18T18:55:46Z
Lists: pgsql-hackers 
On Tue, Jun 30, 2020 at 02:51:38PM -0400, Tom Lane wrote:
> The point remains that exposing the function body's dependencies will
> constrain restore order far more than we are accustomed to see.  It
> might be possible to build examples that flat out can't be restored,
> even granting that we teach pg_dump how to break dependency loops
> by first creating the function with empty body and later redefining
> it with the real body.  (Admittedly, if that's possible then you
> likely could make it happen with views too.  But somehow it seems
> more likely that people would create spaghetti dependencies for
> functions than views.)

Should we be okay releasing v14 without support for breaking function
dependency loops, or does that call for an open item?

-- example
create function f() returns int language sql return 1;
create function g() returns int language sql return f();
create or replace function f() returns int language sql return coalesce(2, g());

-- but when a view can break the cycle, pg_dump still does so
create view v as select 1 as c;
create function f() returns int language sql return coalesce(0, (select count(*) from v));
create or replace view v as select f() as c;

Commits

  1. Don't crash on empty statements in SQL-standard function bodies.

  2. psql: Fix line continuation prompts for unbalanced parentheses

  3. Provide query source text when parsing a SQL-standard function body.

  4. Revert "Cope with NULL query string in ExecInitParallelPlan()."

  5. Undo decision to allow pg_proc.prosrc to be NULL.

  6. SQL-standard function body

  7. Move pg_stat_statements query jumbling to core.

  8. Extend SQL function tests lightly