Greenplum中如果使用循环，并且内部嵌套了子块，在子块中的exit只能跳出子块，不能跳出子块外面的循环。

CREATE OR REPLACE FUNCTION test1(i integer) RETURNS integer AS $$DECLARE count int;BEGIN    count := 1;    LOOP        count := count + 1;        begin            raise notice 'sub xact: %', count;            EXECUTE 'select 1';            IF count > 10 THEN                EXIT;  -- BUG在这里, 只跳出了begin, 没有跳出LOOP                raise notice 'sub xact if: %', count;            END IF;            raise notice 'sub xact end if: %', count;        exception when others then        end;        raise notice 'parent xact: %', count;    END LOOP;    return 1;END$$ LANGUAGE plpgsql;postgres=# select test1(1);NOTICE:  sub xact: 2NOTICE:  sub xact end if: 2NOTICE:  parent xact: 2NOTICE:  sub xact: 3NOTICE:  sub xact end if: 3NOTICE:  parent xact: 3NOTICE:  sub xact: 4NOTICE:  sub xact end if: 4NOTICE:  parent xact: 4NOTICE:  sub xact: 5NOTICE:  sub xact end if: 5NOTICE:  parent xact: 5NOTICE:  sub xact: 6NOTICE:  sub xact end if: 6NOTICE:  parent xact: 6NOTICE:  sub xact: 7NOTICE:  sub xact end if: 7NOTICE:  parent xact: 7NOTICE:  sub xact: 8NOTICE:  sub xact end if: 8NOTICE:  parent xact: 8NOTICE:  sub xact: 9NOTICE:  sub xact end if: 9NOTICE:  parent xact: 9NOTICE:  sub xact: 10NOTICE:  sub xact end if: 10NOTICE:  parent xact: 10NOTICE:  sub xact: 11NOTICE:  parent xact: 11NOTICE:  sub xact: 12NOTICE:  parent xact: 12NOTICE:  sub xact: 13NOTICE:  parent xact: 13NOTICE:  sub xact: 14NOTICE:  parent xact: 14CREATE OR REPLACE FUNCTION test1(i integer) RETURNS integer AS $$DECLARE count int;BEGIN    count := 1;    LOOP        count := count + 1;        begin            raise notice 'sub xact: %', count;            EXECUTE 'select 1';            IF count > 10 THEN                return 0;  -- 改成return, 退出整个函数, 如果要跳出loop, 应该在loop内控制。不能放在LOOP内的sub block执行。            END IF;        exception when others then        end;        raise notice 'parent xact: %', count;    END LOOP;    return 1;END$$ LANGUAGE plpgsql;postgres=# select test1(1);NOTICE:  sub xact: 2NOTICE:  parent xact: 2NOTICE:  sub xact: 3NOTICE:  parent xact: 3NOTICE:  sub xact: 4NOTICE:  parent xact: 4NOTICE:  sub xact: 5NOTICE:  parent xact: 5NOTICE:  sub xact: 6NOTICE:  parent xact: 6NOTICE:  sub xact: 7NOTICE:  parent xact: 7NOTICE:  sub xact: 8NOTICE:  parent xact: 8NOTICE:  sub xact: 9NOTICE:  parent xact: 9NOTICE:  sub xact: 10NOTICE:  parent xact: 10NOTICE:  sub xact: 11 test1 -------     0(1 row)

在PostgreSQL中不存在这个问题。 使用GP时需要注意一下。