如何更改递归函数的架构

Question

作为 ETL 过程的一部分，我正在尝试更改递归函数的架构。喜欢

CREATE FUNCTION some_recursive()
 RETURNS some_type
 LANGUAGE sql
AS $function$ 
 -- do stuff
 some_recursive()
 --do more
$function$
;

我这样做是用

ALTER FUNCTION some_recursive() SET SCHEMA new_schema

这会正确更新，例如依赖视图，将它们从调用some_recursive() 更改为new_schema.some_recursive()。但是递归本身（在函数体内）没有更新，所以当函数被调用时，它会失败。 IE。函数定义后架构更改如下所示：

CREATE FUNCTION new_schema.some_recursive()
 RETURNS some_type
 LANGUAGE sql
AS $function$ 
 -- do stuff
 -- note the next line (no new_schema.-prefix)
 some_recursive()
 --do more
$function$
;

有没有办法改变递归函数的架构？

如果做不到这一点，我也许可以让功能维护者更改其实现。 有没有办法让函数调用类似“self”的东西（即隐式而不指定自己的名称）？

Answer 1

函数中使用的search_path取决于调用函数的会话中设置的search_path。默认情况下，您可以通过更改用户来更改调用该函数的任何用户：

ALTER USER some_user SET search_path TO new_schema,...;  -- you may also want public or others after new_schema

或者，您可以通过稍微修改代码来更改函数中使用的 search_path：

CREATE FUNCTION new_schema.some_recursive()
 RETURNS some_type
 LANGUAGE sql
 SET search_path TO new_schema -- this line changes search_path while inside the function.  It will be reset on function exit.
AS $function$ 
 -- do stuff
 -- note the next line (no new_schema.-prefix)
 some_recursive()
 --do more
$function$
;

您也可以使用此处概述的 PG_CONTEXT：https://stackoverflow.com/a/41889304/895640 但这有点hacky...

CREATE OR REPLACE FUNCTION recursive_test() RETURNS int AS $$
DECLARE
  stack text;
  fcesig regprocedure;
BEGIN
  GET DIAGNOSTICS stack = PG_CONTEXT;
  RAISE NOTICE 'stack: %', stack;
  fcesig := substring(stack from 'function (.*?) line');
  EXECUTE 'SELECT ' || fcesig;
END;
$$ LANGUAGE plpgsql
;

CREATE SCHEMA test2;
alter function recursive_test set schema test2;
NOTICE:  stack: PL/pgSQL function test2.recursive_test() line 6 at GET DIAGNOSTICS
NOTICE:  stack: PL/pgSQL function test2.recursive_test() line 6 at GET DIAGNOSTICS
SQL statement "SELECT test2.recursive_test()"
PL/pgSQL function test2.recursive_test() line 9 at EXECUTE
NOTICE:  stack: PL/pgSQL function test2.recursive_test() line 6 at GET DIAGNOSTICS
SQL statement "SELECT test2.recursive_test()"
PL/pgSQL function test2.recursive_test() line 9 at EXECUTE
SQL statement "SELECT test2.recursive_test()"
PL/pgSQL function test2.recursive_test() line 9 at EXECUTE
NOTICE:  stack: PL/pgSQL function test2.recursive_test() line 6 at GET DIAGNOSTICS
SQL statement "SELECT test2.recursive_test()"
PL/pgSQL function test2.recursive_test() line 9 at EXECUTE
SQL statement "SELECT test2.recursive_test()"
PL/pgSQL function test2.recursive_test() line 9 at EXECUTE
...