postgresql – postgres.超出了plpgsql堆栈深度限制

create or replace function total() 
returns void as $$
declare
  sum int;
begin
  sum = (SELECT count(copy_id) FROM copies);
    update totalbooks
    set all_books = sum
    where num = 1;
  end;
$$language plpgsql;

如果我执行“select total();”它工作得很好所以我做了一个函数触发器,以便它自动更新：

create or replace function total1() returns trigger as $$
begin
   perform (select total());
    return null;
end;
$$language plpgsql;

但在我执行之后：

create trigger total2
after update
on totalbooks
for each row
execute procedure total1();

它给了我一个错误信息：

ERROR:  stack depth limit exceeded
HINT:  Increase the configuration parameter "max_stack_depth" (currently 3072kB),after   ensuring the platform's stack depth limit is adequate.
CONTEXT:  SQL statement "SELECT (SELECT count(copy_id) FROM copies)"
PL/pgSQL function total() line 5 at assignment
SQL statement "SELECT (select total())"
PL/pgSQL function total1() line 3 at PERFORM
SQL statement "update totalbooks
set all_books = sum
where num = 1"
PL/pgSQL function total() line 6 at SQL statement
SQL statement "SELECT (select total())"
PL/pgSQL function total1() line 3 at PERFORM
SQL statement "update totalbooks
set all_books = sum
where num = 1"
PL/pgSQL function total() line 6 at SQL statement
SQL statement "SELECT (select total())"
PL/pgSQL function total1() line 3 at PERFORM
SQL statement "update totalbooks
set all_books = sum
where num = 1"
PL/pgSQL function total() line 6 at SQL statement
SQL statement "SELECT (select total())"
PL/pgSQL function total1() line 3 at PERFORM
SQL statement "update totalbooks
set all_books = sum
where num = 1"
PL/pgSQL function total() line 6 at SQL statement
SQL statement "SELECT (select total())"
PL/pgSQL function total1() line 3 at PERFORM
SQL statement "update totalbooks
set all_books = sum
where num = 1"
PL/pgSQL function total() line 6 at SQL statement
SQL statement "SELECT (select total())"
PL/pgSQL function total1() line 3 at PERFORM
SQL statement "update totalbooks
set all_books = sum
where num = 1"
PL/pgSQL function total() line 6 at SQL statement
SQL statement "SELECT (select total())"

显然我的触发器有问题.请帮忙.

我正在使用Postgres 9.2.4,由Visual C build 1600,64-Bit编译

编辑：

我试过pg_trigger_depth(),但现在触发器不会自动更新？我还是要执行’select total()’

这是我的新代码：

create or replace function total() 
returns void as $$
declare
  sum int;
begin
   sum = (SELECT count(copy_id) FROM copies);
    update totalbooks
    set all_books = sum;
end;
$$language plpgsql;


create or replace function total1() returns trigger as $$
begin
  perform (select total());
  return null;
end;
$$language plpgsql;

create trigger total2
after update
on totalbooks
for each row
WHEN (pg_trigger_depth()=0)
execute procedure total1();